[syzbot] [dri?] KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a5b6244cf87c Merge tag 'block-6.8-2024-02-10' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15e9ad50180000
kernel config: https://syzkaller.appspot.com/x/.config?x=53985487b59d9442
dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-a5b6244c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/08ca7654741a/vmlinux-a5b6244c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0396d079aa1e/bzImage-a5b6244c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0f999d...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x84f/0x930 drivers/gpu/drm/drm_atomic_helper.c:1661
Read of size 1 at addr ffff888026066009 by task kworker/u16:8/1094

CPU: 2 PID: 1094 Comm: kworker/u16:8 Not tainted 6.8.0-rc3-syzkaller-00293-ga5b6244cf87c #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events_unbound commit_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:488
kasan_report+0xda/0x110 mm/kasan/report.c:601
drm_atomic_helper_wait_for_vblanks.part.0+0x84f/0x930 drivers/gpu/drm/drm_atomic_helper.c:1661
drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1657 [inline]
drm_atomic_helper_commit_tail+0xcb/0xf0 drivers/gpu/drm/drm_atomic_helper.c:1757
commit_tail+0x356/0x410 drivers/gpu/drm/drm_atomic_helper.c:1834
process_one_work+0x889/0x15e0 kernel/workqueue.c:2633
process_scheduled_works kernel/workqueue.c:2706 [inline]
worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787
kthread+0x2c6/0x3b0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
</TASK>

Allocated by task 16480:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:389
kmalloc include/linux/slab.h:590 [inline]
drm_atomic_helper_crtc_duplicate_state+0x70/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:177
drm_atomic_get_crtc_state+0x162/0x440 drivers/gpu/drm/drm_atomic.c:362
page_flip_common+0x57/0x320 drivers/gpu/drm/drm_atomic_helper.c:3629
drm_atomic_helper_page_flip+0xb6/0x190 drivers/gpu/drm/drm_atomic_helper.c:3690
drm_mode_page_flip_ioctl+0x103f/0x1470 drivers/gpu/drm/drm_plane.c:1489
drm_ioctl_kernel+0x1ec/0x3e0 drivers/gpu/drm/drm_ioctl.c:744
drm_ioctl+0x5d8/0xc00 drivers/gpu/drm/drm_ioctl.c:841
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl fs/ioctl.c:857 [inline]
__x64_sys_ioctl+0x193/0x220 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 16474:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
poison_slab_object mm/kasan/common.c:241 [inline]
__kasan_slab_free+0x121/0x1c0 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kfree+0x124/0x370 mm/slub.c:4409
drm_atomic_state_default_clear+0x3aa/0xde0 drivers/gpu/drm/drm_atomic.c:225
drm_atomic_state_clear drivers/gpu/drm/drm_atomic.c:294 [inline]
__drm_atomic_state_free+0x185/0x2b0 drivers/gpu/drm/drm_atomic.c:311
kref_put include/linux/kref.h:65 [inline]
drm_atomic_state_put include/drm/drm_atomic.h:490 [inline]
drm_client_modeset_commit_atomic+0x6db/0x810 drivers/gpu/drm/drm_client_modeset.c:1057
drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1154
drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1180
__drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:251 [inline]
__drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:230 [inline]
drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:278 [inline]
drm_fb_helper_lastclose+0xc7/0x160 drivers/gpu/drm/drm_fb_helper.c:2005
drm_fbdev_generic_client_restore+0x2c/0x40 drivers/gpu/drm/drm_fbdev_generic.c:258
drm_client_dev_restore+0x188/0x2a0 drivers/gpu/drm/drm_client.c:247
drm_release+0x32f/0x3e0 drivers/gpu/drm/drm_file.c:437
__fput+0x270/0xb80 fs/file_table.c:376
__fput_sync+0x47/0x50 fs/file_table.c:461
__do_sys_close fs/open.c:1554 [inline]
__se_sys_close fs/open.c:1539 [inline]
__x64_sys_close+0x87/0x100 fs/open.c:1539
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6f/0x77

The buggy address belongs to the object at ffff888026066000
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 9 bytes inside of
freed 512-byte region [ffff888026066000, ffff888026066200)

The buggy address belongs to the physical page:
page:ffffea0000981900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26064
head:ffffea0000981900 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888014c42c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 28, tgid 28 (kworker/1:0), ts 50737339083, free_ts 50338469746
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3311
__alloc_pages+0x22f/0x2440 mm/page_alloc.c:4567
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2190 [inline]
allocate_slab mm/slub.c:2354 [inline]
new_slab+0xcc/0x3a0 mm/slub.c:2407
___slab_alloc+0x4af/0x19a0 mm/slub.c:3540
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3625
__slab_alloc_node mm/slub.c:3678 [inline]
slab_alloc_node mm/slub.c:3850 [inline]
kmalloc_trace+0x30b/0x340 mm/slub.c:4007
kmalloc include/linux/slab.h:590 [inline]
kzalloc include/linux/slab.h:711 [inline]
mca_alloc net/ipv6/mcast.c:880 [inline]
__ipv6_dev_mc_inc+0x2b7/0xc50 net/ipv6/mcast.c:936
addrconf_join_solict net/ipv6/addrconf.c:2192 [inline]
addrconf_dad_begin net/ipv6/addrconf.c:4037 [inline]
addrconf_dad_work+0x232/0x14c0 net/ipv6/addrconf.c:4162
process_one_work+0x889/0x15e0 kernel/workqueue.c:2633
process_scheduled_works kernel/workqueue.c:2706 [inline]
worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787
kthread+0x2c6/0x3b0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
page last free pid 5180 tgid 5180 stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2346
free_unref_page+0x33/0x3c0 mm/page_alloc.c:2486
qlink_free mm/kasan/quarantine.c:160 [inline]
qlist_free_all+0x58/0x150 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:324
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3813 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
kmalloc_trace+0x148/0x340 mm/slub.c:4007
kmalloc include/linux/slab.h:590 [inline]
kzalloc include/linux/slab.h:711 [inline]
ref_tracker_alloc+0x17c/0x5b0 lib/ref_tracker.c:203
__netdev_tracker_alloc include/linux/netdevice.h:4147 [inline]
netdev_hold include/linux/netdevice.h:4176 [inline]
netdev_hold include/linux/netdevice.h:4171 [inline]
netdev_queue_add_kobject net/core/net-sysfs.c:1703 [inline]
netdev_queue_update_kobjects+0x1b3/0x520 net/core/net-sysfs.c:1758
register_queue_kobjects net/core/net-sysfs.c:1819 [inline]
netdev_register_kobject+0x290/0x3f0 net/core/net-sysfs.c:2059
register_netdevice+0x1392/0x1db0 net/core/dev.c:10261
geneve_configure+0x6a7/0xa10 drivers/net/geneve.c:1366
geneve_newlink+0x12f/0x2b0 drivers/net/geneve.c:1617
rtnl_newlink_create net/core/rtnetlink.c:3515 [inline]
__rtnl_newlink+0x1197/0x1960 net/core/rtnetlink.c:3735
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3748
rtnetlink_rcv_msg+0x3c7/0xe10 net/core/rtnetlink.c:6615
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2543

Memory state around the buggy address:
ffff888026065f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888026065f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888026066000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888026066080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888026066100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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If the report is already addressed, let syzbot know by replying with:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: c664e16bb1ba Merge tag 'docs-6.8-fixes2' of git://git.lwn...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14f8d1e0180000
kernel config: https://syzkaller.appspot.com/x/.config?x=df82262440d95bc4

dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1086cd48180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11fcdba2180000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-c664e16b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c838390fdb6c/vmlinux-c664e16b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d25123cb1896/bzImage-c664e16b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0f999d...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x84f/0x930 drivers/gpu/drm/drm_atomic_helper.c:1661

Read of size 1 at addr ffff88802d6f0409 by task kworker/u16:1/13

CPU: 1 PID: 13 Comm: kworker/u16:1 Not tainted 6.8.0-rc4-syzkaller-00005-gc664e16bb1ba #0

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events_unbound commit_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:488
kasan_report+0xda/0x110 mm/kasan/report.c:601
drm_atomic_helper_wait_for_vblanks.part.0+0x84f/0x930 drivers/gpu/drm/drm_atomic_helper.c:1661
drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1657 [inline]
drm_atomic_helper_commit_tail+0xcb/0xf0 drivers/gpu/drm/drm_atomic_helper.c:1757
commit_tail+0x356/0x410 drivers/gpu/drm/drm_atomic_helper.c:1834
process_one_work+0x889/0x15e0 kernel/workqueue.c:2633
process_scheduled_works kernel/workqueue.c:2706 [inline]
worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787
kthread+0x2c6/0x3b0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
</TASK>

Allocated by task 5401:

kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:389
kmalloc include/linux/slab.h:590 [inline]
drm_atomic_helper_crtc_duplicate_state+0x70/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:177
drm_atomic_get_crtc_state+0x162/0x440 drivers/gpu/drm/drm_atomic.c:362
page_flip_common+0x57/0x320 drivers/gpu/drm/drm_atomic_helper.c:3629
drm_atomic_helper_page_flip+0xb6/0x190 drivers/gpu/drm/drm_atomic_helper.c:3690
drm_mode_page_flip_ioctl+0x103f/0x1470 drivers/gpu/drm/drm_plane.c:1489
drm_ioctl_kernel+0x1ec/0x3e0 drivers/gpu/drm/drm_ioctl.c:744
drm_ioctl+0x5d8/0xc00 drivers/gpu/drm/drm_ioctl.c:841
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl fs/ioctl.c:857 [inline]
__x64_sys_ioctl+0x193/0x220 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 5401:

The buggy address belongs to the object at ffff88802d6f0400

which belongs to the cache kmalloc-512 of size 512
The buggy address is located 9 bytes inside of

freed 512-byte region [ffff88802d6f0400, ffff88802d6f0600)

The buggy address belongs to the physical page:

page:ffffea0000b5bc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2d6f0
head:ffffea0000b5bc00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0

flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()

raw: 00fff00000000840 ffff888014c42c80 dead000000000122 0000000000000000

raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated

page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5401, tgid 5401 (syz-executor102), ts 53592743984, free_ts 53573722996

set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3311
__alloc_pages+0x22f/0x2440 mm/page_alloc.c:4567
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2190 [inline]
allocate_slab mm/slub.c:2354 [inline]
new_slab+0xcc/0x3a0 mm/slub.c:2407
___slab_alloc+0x4af/0x19a0 mm/slub.c:3540
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3625
__slab_alloc_node mm/slub.c:3678 [inline]
slab_alloc_node mm/slub.c:3850 [inline]
kmalloc_trace+0x30b/0x340 mm/slub.c:4007
kmalloc include/linux/slab.h:590 [inline]
kzalloc include/linux/slab.h:711 [inline]

drm_master_create+0x43/0x4d0 drivers/gpu/drm/drm_auth.c:136
drm_new_set_master+0xd6/0x450 drivers/gpu/drm/drm_auth.c:172
drm_master_open+0x181/0x1f0 drivers/gpu/drm/drm_auth.c:342
drm_open_helper+0x3fc/0x500 drivers/gpu/drm/drm_file.c:330
drm_open+0x1a0/0x490 drivers/gpu/drm/drm_file.c:380
drm_stub_open+0x28e/0x430 drivers/gpu/drm/drm_drv.c:1046
chrdev_open+0x26d/0x6f0 fs/char_dev.c:414
do_dentry_open+0x8da/0x18c0 fs/open.c:953
do_open fs/namei.c:3641 [inline]
path_openat+0x1e00/0x29a0 fs/namei.c:3798
page last free pid 5398 tgid 5398 stack trace:

reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2346
free_unref_page+0x33/0x3c0 mm/page_alloc.c:2486

rcu_do_batch kernel/rcu/tree.c:2190 [inline]
rcu_core+0x819/0x1680 kernel/rcu/tree.c:2465
__do_softirq+0x21c/0x8e7 kernel/softirq.c:553

Memory state around the buggy address:

ffff88802d6f0300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802d6f0380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802d6f0400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802d6f0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802d6f0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[Hillf Danton]

On Tue, 13 Feb 2024 06:08:15 -0800

> HEAD commit: c664e16bb1ba Merge tag 'docs-6.8-fixes2' of git://git.lwn...
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11fcdba2180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

--- x/drivers/gpu/drm/drm_client_modeset.c
+++ y/drivers/gpu/drm/drm_client_modeset.c
@@ -1062,6 +1062,7 @@ out_ctx:
return ret;

backoff:
+ cancel_work_sync(&state->commit_work);
drm_atomic_state_clear(state);
drm_modeset_backoff(&ctx);

--

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
[ 12.100286][ T1] Non-volatile memory driver v1.3
[ 12.113616][ T1] Linux agpgart interface v0.103
[ 12.123143][ T1] ACPI: bus type drm_connector registered
[ 12.142579][ T1] [drm] Initialized vgem 1.0.0 20120112 for vgem on minor 0
[ 12.162590][ T1] [drm] Initialized vkms 1.0.0 20180514 for vkms on minor 1
[ 12.287128][ T1] Console: switching to colour frame buffer device 128x48
[ 12.310428][ T1] platform vkms: [drm] fb0: vkmsdrmfb frame buffer device
[ 12.331206][ C0] vkms_vblank_simulate: vblank timer overrun
[ 12.336575][ T1] usbcore: registered new interface driver udl
[ 12.342353][ T1] [drm] pci: virtio-vga detected at 0000:00:01.0
[ 12.363944][ T1] virtio-pci 0000:00:01.0: vgaarb: deactivate vga console
[ 12.373522][ T1] [drm] features: -virgl +edid -resource_blob -host_visible
[ 12.373539][ T1] [drm] features: -context_init
[ 12.394195][ T1] [drm] number of scanouts: 1
[ 12.397944][ T1] [drm] number of cap sets: 0
[ 12.411757][ T1] [drm] Initialized virtio_gpu 0.1.0 0 for 0000:00:01.0 on minor 2
[ 12.494144][ T1] fbcon: virtio_gpudrmfb (fb1) is primary device
[ 12.494166][ T1] fbcon: Remapping primary device, fb1, to tty 1-63
[ 12.529275][ T1] ------------[ cut here ]------------
[ 12.529360][ T1] WARNING: CPU: 0 PID: 1 at kernel/workqueue.c:3403 __flush_work+0x879/0xa20
[ 12.529392][ T1] Modules linked in:
[ 12.529406][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc4-syzkaller-g7e90b5c295ec-dirty #0
[ 12.529424][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 12.529439][ T1] RIP: 0010:__flush_work+0x879/0xa20
[ 12.529458][ T1] Code: c7 60 d1 7a 8d 48 8d 35 00 00 00 00 e8 80 c0 12 00 45 31 ed e9 cc fc ff ff e8 83 5a 33 00 90 0f 0b 90 eb ed e8 78 5a 33 00 90 <0f> 0b 90 eb e2 e8 6d 5a 33 00 e8 68 5a 33 00 e8 63 5a 33 00 48 8b
[ 12.529476][ T1] RSP: 0000:ffffc90000046fc0 EFLAGS: 00010293
[ 12.529493][ T1] RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff8157ebdd
[ 12.529505][ T1] RDX: ffff8880166d8000 RSI: ffffffff8157f3a8 RDI: 0000000000000001
[ 12.529517][ T1] RBP: ffff88801e1f1048 R08: 0000000000000001 R09: 0000000000000000
[ 12.529529][ T1] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[ 12.529541][ T1] R13: 0000000000000001 R14: ffff88801e1f1060 R15: 0000000000000001
[ 12.529559][ T1] FS: 0000000000000000(0000) GS:ffff88806b200000(0000) knlGS:0000000000000000
[ 12.529599][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 12.529623][ T1] CR2: ffff88817ffff000 CR3: 000000000d57a000 CR4: 0000000000350ef0
[ 12.529636][ T1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 12.529647][ T1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 12.529664][ T1] Call Trace:
[ 12.529672][ T1] <TASK>
[ 12.529681][ T1] ? show_regs+0x8f/0xa0
[ 12.529709][ T1] ? __warn+0xe6/0x390
[ 12.529734][ T1] ? __flush_work+0x879/0xa20
[ 12.529751][ T1] ? report_bug+0x3c0/0x580
[ 12.529774][ T1] ? handle_bug+0x3d/0x70
[ 12.529792][ T1] ? exc_invalid_op+0x17/0x50
[ 12.529815][ T1] ? asm_exc_invalid_op+0x1a/0x20
[ 12.529905][ T1] ? __flush_work+0xad/0xa20
[ 12.529919][ T1] ? __flush_work+0x878/0xa20
[ 12.529935][ T1] ? __flush_work+0x879/0xa20
[ 12.529951][ T1] ? rcu_is_watching+0x12/0xc0
[ 12.529999][ T1] ? __pfx___flush_work+0x10/0x10
[ 12.530012][ T1] ? __pfx_mark_lock+0x10/0x10
[ 12.530034][ T1] ? mark_held_locks+0x9f/0xe0
[ 12.530052][ T1] __cancel_work_timer+0x3f3/0x590
[ 12.530068][ T1] ? __pfx___cancel_work_timer+0x10/0x10
[ 12.530083][ T1] ? modeset_lock+0x10e/0x6c0
[ 12.530102][ T1] ? drm_modeset_lock+0x60/0x90
[ 12.530120][ T1] ? drm_atomic_get_crtc_state+0xd2/0x440
[ 12.530144][ T1] ? drm_atomic_get_plane_state+0x17a/0x590
[ 12.530168][ T1] drm_client_modeset_commit_atomic+0x294/0x820
[ 12.530195][ T1] ? trace_contention_end+0xda/0x110
[ 12.530217][ T1] ? __pfx_drm_client_modeset_commit_atomic+0x10/0x10
[ 12.530305][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 12.530329][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 12.530351][ T1] ? __pfx___mutex_unlock_slowpath+0x10/0x10
[ 12.530374][ T1] drm_client_modeset_commit_locked+0x14d/0x580
[ 12.530397][ T1] drm_fb_helper_pan_display+0x2a5/0x990
[ 12.530416][ T1] fb_pan_display+0x477/0x7d0
[ 12.530436][ T1] ? __pfx_drm_fb_helper_pan_display+0x10/0x10
[ 12.530454][ T1] bit_update_start+0x49/0x1f0
[ 12.530472][ T1] fbcon_switch+0xbbf/0x12f0
[ 12.530489][ T1] ? __pfx_fbcon_switch+0x10/0x10
[ 12.530507][ T1] ? __pfx_bit_cursor+0x10/0x10
[ 12.530525][ T1] ? fbcon_cursor+0x3e0/0x540
[ 12.530542][ T1] ? is_console_locked+0x9/0x20
[ 12.530560][ T1] ? con_is_visible+0x65/0x150
[ 12.530581][ T1] redraw_screen+0x2bf/0x760
[ 12.530596][ T1] ? fbcon_prepare_logo+0x926/0xc80
[ 12.530615][ T1] ? __pfx_redraw_screen+0x10/0x10
[ 12.530631][ T1] set_con2fb_map+0x796/0x1060
[ 12.530649][ T1] fbcon_fb_registered+0x21d/0x670
[ 12.530667][ T1] ? fb_var_to_videomode+0x4c9/0x690
[ 12.530691][ T1] register_framebuffer+0x4b2/0x860
[ 12.530714][ T1] ? __pfx_register_framebuffer+0x10/0x10
[ 12.530738][ T1] ? drm_fbdev_generic_helper_fb_probe+0x4e2/0x6d0
[ 12.530756][ T1] __drm_fb_helper_initial_config_and_unlock+0xd82/0x1650
[ 12.530779][ T1] ? __pfx___drm_fb_helper_initial_config_and_unlock+0x10/0x10
[ 12.530802][ T1] drm_fb_helper_initial_config+0x44/0x60
[ 12.530825][ T1] drm_fbdev_generic_client_hotplug+0x1a6/0x280
[ 12.530843][ T1] ? __pfx_drm_fbdev_generic_client_hotplug+0x10/0x10
[ 12.530860][ T1] drm_client_register+0x195/0x280
[ 12.530884][ T1] drm_fbdev_generic_setup+0x184/0x340
[ 12.530901][ T1] virtio_gpu_probe+0x29d/0x4e0
[ 12.530927][ T1] virtio_dev_probe+0x5ff/0x9b0
[ 12.530943][ T1] ? __pfx_virtio_dev_probe+0x10/0x10
[ 12.530958][ T1] really_probe+0x23a/0xcb0
[ 12.530981][ T1] __driver_probe_device+0x1de/0x4b0
[ 12.530996][ T1] ? _raw_spin_unlock_irqrestore+0x52/0x80
[ 12.531020][ T1] driver_probe_device+0x4c/0x1b0
[ 12.531037][ T1] __driver_attach+0x283/0x580
[ 12.531053][ T1] ? __pfx___driver_attach+0x10/0x10
[ 12.531068][ T1] bus_for_each_dev+0x13c/0x1d0
[ 12.531087][ T1] ? __pfx_bus_for_each_dev+0x10/0x10
[ 12.531108][ T1] bus_add_driver+0x2ed/0x640
[ 12.531128][ T1] ? __pfx_virtio_gpu_driver_init+0x10/0x10
[ 12.531149][ T1] driver_register+0x15c/0x4b0
[ 12.531168][ T1] do_one_initcall+0x11c/0x670
[ 12.531191][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 12.531214][ T1] ? trace_kmalloc+0x2e/0xb0
[ 12.531238][ T1] ? __kmalloc+0x218/0x440
[ 12.531258][ T1] kernel_init_freeable+0x68d/0xc10
[ 12.531286][ T1] ? __pfx_kernel_init+0x10/0x10
[ 12.531306][ T1] kernel_init+0x1c/0x2a0
[ 12.531325][ T1] ? __pfx_kernel_init+0x10/0x10
[ 12.531343][ T1] ret_from_fork+0x45/0x80
[ 12.531366][ T1] ? __pfx_kernel_init+0x10/0x10
[ 12.531390][ T1] ret_from_fork_asm+0x1b/0x30
[ 12.531420][ T1] </TASK>
[ 12.531431][ T1] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 12.531437][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc4-syzkaller-g7e90b5c295ec-dirty #0
[ 12.531458][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 12.531469][ T1] Call Trace:
[ 12.531474][ T1] <TASK>
[ 12.531479][ T1] dump_stack_lvl+0xd9/0x1b0
[ 12.531497][ T1] panic+0x6ee/0x7a0
[ 12.531516][ T1] ? __pfx_panic+0x10/0x10
[ 12.531534][ T1] ? show_trace_log_lvl+0x363/0x500
[ 12.531557][ T1] ? check_panic_on_warn+0x1f/0xb0
[ 12.531578][ T1] ? __flush_work+0x879/0xa20
[ 12.531593][ T1] check_panic_on_warn+0xab/0xb0
[ 12.531616][ T1] __warn+0xf2/0x390
[ 12.533508][ T1] ? __flush_work+0x879/0xa20
[ 12.533508][ T1] report_bug+0x3c0/0x580
[ 12.533508][ T1] handle_bug+0x3d/0x70
[ 12.533508][ T1] exc_invalid_op+0x17/0x50
[ 12.533508][ T1] asm_exc_invalid_op+0x1a/0x20
[ 12.533508][ T1] RIP: 0010:__flush_work+0x879/0xa20
[ 12.533508][ T1] Code: c7 60 d1 7a 8d 48 8d 35 00 00 00 00 e8 80 c0 12 00 45 31 ed e9 cc fc ff ff e8 83 5a 33 00 90 0f 0b 90 eb ed e8 78 5a 33 00 90 <0f> 0b 90 eb e2 e8 6d 5a 33 00 e8 68 5a 33 00 e8 63 5a 33 00 48 8b
[ 12.533508][ T1] RSP: 0000:ffffc90000046fc0 EFLAGS: 00010293
[ 12.533508][ T1] RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff8157ebdd
[ 12.533508][ T1] RDX: ffff8880166d8000 RSI: ffffffff8157f3a8 RDI: 0000000000000001
[ 12.533508][ T1] RBP: ffff88801e1f1048 R08: 0000000000000001 R09: 0000000000000000
[ 12.533508][ T1] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[ 12.533508][ T1] R13: 0000000000000001 R14: ffff88801e1f1060 R15: 0000000000000001
[ 12.533508][ T1] ? __flush_work+0xad/0xa20
[ 12.533508][ T1] ? __flush_work+0x878/0xa20
[ 12.533508][ T1] ? rcu_is_watching+0x12/0xc0
[ 12.533508][ T1] ? __pfx___flush_work+0x10/0x10
[ 12.533508][ T1] ? __pfx_mark_lock+0x10/0x10
[ 12.533508][ T1] ? mark_held_locks+0x9f/0xe0
[ 12.533508][ T1] __cancel_work_timer+0x3f3/0x590
[ 12.533508][ T1] ? __pfx___cancel_work_timer+0x10/0x10
[ 12.533508][ T1] ? modeset_lock+0x10e/0x6c0
[ 12.533508][ T1] ? drm_modeset_lock+0x60/0x90
[ 12.533508][ T1] ? drm_atomic_get_crtc_state+0xd2/0x440
[ 12.533508][ T1] ? drm_atomic_get_plane_state+0x17a/0x590
[ 12.533508][ T1] drm_client_modeset_commit_atomic+0x294/0x820
[ 12.533508][ T1] ? trace_contention_end+0xda/0x110
[ 12.533508][ T1] ? __pfx_drm_client_modeset_commit_atomic+0x10/0x10
[ 12.533508][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 12.533508][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 12.533508][ T1] ? __pfx___mutex_unlock_slowpath+0x10/0x10
[ 12.533508][ T1] drm_client_modeset_commit_locked+0x14d/0x580
[ 12.533508][ T1] drm_fb_helper_pan_display+0x2a5/0x990
[ 12.533508][ T1] fb_pan_display+0x477/0x7d0
[ 12.533508][ T1] ? __pfx_drm_fb_helper_pan_display+0x10/0x10
[ 12.533508][ T1] bit_update_start+0x49/0x1f0
[ 12.533508][ T1] fbcon_switch+0xbbf/0x12f0
[ 12.533508][ T1] ? __pfx_fbcon_switch+0x10/0x10
[ 12.533508][ T1] ? __pfx_bit_cursor+0x10/0x10
[ 12.533508][ T1] ? fbcon_cursor+0x3e0/0x540
[ 12.533508][ T1] ? is_console_locked+0x9/0x20
[ 12.533508][ T1] ? con_is_visible+0x65/0x150
[ 12.533508][ T1] redraw_screen+0x2bf/0x760
[ 12.533508][ T1] ? fbcon_prepare_logo+0x926/0xc80
[ 12.533508][ T1] ? __pfx_redraw_screen+0x10/0x10
[ 12.533508][ T1] set_con2fb_map+0x796/0x1060
[ 12.533508][ T1] fbcon_fb_registered+0x21d/0x670
[ 12.533508][ T1] ? fb_var_to_videomode+0x4c9/0x690
[ 12.533508][ T1] register_framebuffer+0x4b2/0x860
[ 12.533508][ T1] ? __pfx_register_framebuffer+0x10/0x10
[ 12.533508][ T1] ? drm_fbdev_generic_helper_fb_probe+0x4e2/0x6d0
[ 12.533508][ T1] __drm_fb_helper_initial_config_and_unlock+0xd82/0x1650
[ 12.533508][ T1] ? __pfx___drm_fb_helper_initial_config_and_unlock+0x10/0x10
[ 12.533508][ T1] drm_fb_helper_initial_config+0x44/0x60
[ 12.533508][ T1] drm_fbdev_generic_client_hotplug+0x1a6/0x280
[ 12.533508][ T1] ? __pfx_drm_fbdev_generic_client_hotplug+0x10/0x10
[ 12.533508][ T1] drm_client_register+0x195/0x280
[ 12.533508][ T1] drm_fbdev_generic_setup+0x184/0x340
[ 12.533508][ T1] virtio_gpu_probe+0x29d/0x4e0
[ 12.533508][ T1] virtio_dev_probe+0x5ff/0x9b0
[ 12.533508][ T1] ? __pfx_virtio_dev_probe+0x10/0x10
[ 12.533508][ T1] really_probe+0x23a/0xcb0
[ 12.533508][ T1] __driver_probe_device+0x1de/0x4b0
[ 12.533508][ T1] ? _raw_spin_unlock_irqrestore+0x52/0x80
[ 12.533508][ T1] driver_probe_device+0x4c/0x1b0
[ 12.533508][ T1] __driver_attach+0x283/0x580
[ 12.533508][ T1] ? __pfx___driver_attach+0x10/0x10
[ 12.533508][ T1] bus_for_each_dev+0x13c/0x1d0
[ 12.533508][ T1] ? __pfx_bus_for_each_dev+0x10/0x10
[ 12.533508][ T1] bus_add_driver+0x2ed/0x640
[ 12.533508][ T1] ? __pfx_virtio_gpu_driver_init+0x10/0x10
[ 12.533508][ T1] driver_register+0x15c/0x4b0
[ 12.533508][ T1] do_one_initcall+0x11c/0x670
[ 12.533508][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 12.533508][ T1] ? trace_kmalloc+0x2e/0xb0
[ 12.533508][ T1] ? __kmalloc+0x218/0x440
[ 12.533508][ T1] kernel_init_freeable+0x68d/0xc10
[ 12.533508][ T1] ? __pfx_kernel_init+0x10/0x10
[ 12.533508][ T1] kernel_init+0x1c/0x2a0
[ 12.533508][ T1] ? __pfx_kernel_init+0x10/0x10
[ 12.533508][ T1] ret_from_fork+0x45/0x80
[ 12.533508][ T1] ? __pfx_kernel_init+0x10/0x10
[ 12.533508][ T1] ret_from_fork_asm+0x1b/0x30
[ 12.533508][ T1] </TASK>
[ 12.533508][ T1] Kernel Offset: disabled


syzkaller build log:
go env (err=<nil>)
GO111MODULE="auto"
GOARCH="amd64"
GOBIN=""
GOCACHE="/syzkaller/.cache/go-build"
GOENV="/syzkaller/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/syzkaller/jobs/linux/gopath/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/syzkaller/jobs/linux/gopath"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.20.1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod"
GOWORK=""
CGO_CFLAGS="-O2 -g"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-O2 -g"
CGO_FFLAGS="-O2 -g"
CGO_LDFLAGS="-O2 -g"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3587630670=/tmp/go-build -gno-record-gcc-switches"

git status (err=<nil>)
HEAD detached at e66542d78
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:32: run command via tools/syz-env for best compatibility, see:
Makefile:33: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' ./sys/syz-sysgen | grep -q false || go install ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=e66542d78f1cf0c783877440cd239a11fb73fb15 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240213-111349'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-fuzzer github.com/google/syzkaller/syz-fuzzer
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=e66542d78f1cf0c783877440cd239a11fb73fb15 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240213-111349'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=e66542d78f1cf0c783877440cd239a11fb73fb15 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240213-111349'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-stress github.com/google/syzkaller/tools/syz-stress
mkdir -p ./bin/linux_amd64
gcc -o ./bin/linux_amd64/syz-executor executor/executor.cc \
-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w -DGOOS_linux=1 -DGOARCH_amd64=1 \
-DHOSTGOOS_linux=1 -DGIT_REVISION=\"e66542d78f1cf0c783877440cd239a11fb73fb15\"


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=16112678180000


Tested on:

commit: 7e90b5c2 Merge tag 'trace-tools-v6.8-rc4' of git://git..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

kernel config: https://syzkaller.appspot.com/x/.config?x=df82262440d95bc4
dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=10c28d14180000

[Hillf Danton]

On Tue, 13 Feb 2024 06:08:15 -0800

> HEAD commit: c664e16bb1ba Merge tag 'docs-6.8-fixes2' of git://git.lwn...
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11fcdba2180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

--- x/drivers/gpu/drm/drm_client_modeset.c
+++ y/drivers/gpu/drm/drm_client_modeset.c

@@ -1062,6 +1062,8 @@ out_ctx:
return ret;

backoff:
+ if (state->commit_work.func)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks

==================================================================
BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x84f/0x930 drivers/gpu/drm/drm_atomic_helper.c:1661

Read of size 1 at addr ffff88802a5f2409 by task kworker/u16:9/1096

CPU: 0 PID: 1096 Comm: kworker/u16:9 Not tainted 6.8.0-rc4-syzkaller-g7e90b5c295ec-dirty #0

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014

Workqueue: events_unbound commit_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:488
kasan_report+0xda/0x110 mm/kasan/report.c:601
drm_atomic_helper_wait_for_vblanks.part.0+0x84f/0x930 drivers/gpu/drm/drm_atomic_helper.c:1661
drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1657 [inline]
drm_atomic_helper_commit_tail+0xcb/0xf0 drivers/gpu/drm/drm_atomic_helper.c:1757
commit_tail+0x356/0x410 drivers/gpu/drm/drm_atomic_helper.c:1834
process_one_work+0x889/0x15e0 kernel/workqueue.c:2633
process_scheduled_works kernel/workqueue.c:2706 [inline]
worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787
kthread+0x2c6/0x3b0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
</TASK>

Allocated by task 5653:

kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:389
kmalloc include/linux/slab.h:590 [inline]
drm_atomic_helper_crtc_duplicate_state+0x70/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:177
drm_atomic_get_crtc_state+0x162/0x440 drivers/gpu/drm/drm_atomic.c:362
page_flip_common+0x57/0x320 drivers/gpu/drm/drm_atomic_helper.c:3629
drm_atomic_helper_page_flip+0xb6/0x190 drivers/gpu/drm/drm_atomic_helper.c:3690
drm_mode_page_flip_ioctl+0x103f/0x1470 drivers/gpu/drm/drm_plane.c:1489
drm_ioctl_kernel+0x1ec/0x3e0 drivers/gpu/drm/drm_ioctl.c:744
drm_ioctl+0x5d8/0xc00 drivers/gpu/drm/drm_ioctl.c:841
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl fs/ioctl.c:857 [inline]
__x64_sys_ioctl+0x193/0x220 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 5652:

kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640
poison_slab_object mm/kasan/common.c:241 [inline]
__kasan_slab_free+0x121/0x1c0 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kfree+0x124/0x370 mm/slub.c:4409
drm_atomic_state_default_clear+0x3aa/0xde0 drivers/gpu/drm/drm_atomic.c:225
drm_atomic_state_clear drivers/gpu/drm/drm_atomic.c:294 [inline]
__drm_atomic_state_free+0x185/0x2b0 drivers/gpu/drm/drm_atomic.c:311
kref_put include/linux/kref.h:65 [inline]
drm_atomic_state_put include/drm/drm_atomic.h:490 [inline]

drm_client_modeset_commit_atomic+0x70f/0x850 drivers/gpu/drm/drm_client_modeset.c:1057
drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1156
drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1182

__drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:251 [inline]
__drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:230 [inline]
drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:278 [inline]
drm_fb_helper_lastclose+0xc7/0x160 drivers/gpu/drm/drm_fb_helper.c:2005
drm_fbdev_generic_client_restore+0x2c/0x40 drivers/gpu/drm/drm_fbdev_generic.c:258
drm_client_dev_restore+0x188/0x2a0 drivers/gpu/drm/drm_client.c:247
drm_release+0x32f/0x3e0 drivers/gpu/drm/drm_file.c:437
__fput+0x270/0xb80 fs/file_table.c:376
__fput_sync+0x47/0x50 fs/file_table.c:461
__do_sys_close fs/open.c:1554 [inline]
__se_sys_close fs/open.c:1539 [inline]
__x64_sys_close+0x87/0x100 fs/open.c:1539
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6f/0x77

The buggy address belongs to the object at ffff88802a5f2400

which belongs to the cache kmalloc-512 of size 512
The buggy address is located 9 bytes inside of

freed 512-byte region [ffff88802a5f2400, ffff88802a5f2600)

The buggy address belongs to the physical page:

page:ffffea0000a97c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802a5f3c00 pfn:0x2a5f0
head:ffffea0000a97c00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000a40(workingset|slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000a40 ffff888014c42c80 ffffea0000a4e410 ffffea00009bd610
raw: ffff88802a5f3c00 000000000010000b 00000001ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as allocated

page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5166, tgid 5166 (syz-executor.0), ts 45262333507, free_ts 42769982140

set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3311
__alloc_pages+0x22f/0x2440 mm/page_alloc.c:4567
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2190 [inline]
allocate_slab mm/slub.c:2354 [inline]
new_slab+0xcc/0x3a0 mm/slub.c:2407
___slab_alloc+0x4af/0x19a0 mm/slub.c:3540
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3625
__slab_alloc_node mm/slub.c:3678 [inline]
slab_alloc_node mm/slub.c:3850 [inline]

__do_kmalloc_node mm/slub.c:3980 [inline]
__kmalloc+0x3b8/0x440 mm/slub.c:3994
kmalloc include/linux/slab.h:594 [inline]
kzalloc include/linux/slab.h:711 [inline]
fib6_info_alloc+0x40/0x100 net/ipv6/ip6_fib.c:155
ip6_route_info_create+0x337/0x1b70 net/ipv6/route.c:3749
ip6_route_add+0x26/0x150 net/ipv6/route.c:3843
addrconf_prefix_route+0x2fe/0x510 net/ipv6/addrconf.c:2437
inet6_addr_add+0x609/0xbe0 net/ipv6/addrconf.c:3004
inet6_rtm_newaddr+0x11de/0x1ab0 net/ipv6/addrconf.c:4976

rtnetlink_rcv_msg+0x3c7/0xe10 net/core/rtnetlink.c:6615
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2543

netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0x542/0x820 net/netlink/af_netlink.c:1367
page last free pid 5115 tgid 5115 stack trace:

reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2346
free_unref_page+0x33/0x3c0 mm/page_alloc.c:2486

qlink_free mm/kasan/quarantine.c:160 [inline]
qlist_free_all+0x58/0x150 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:324
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3813 [inline]

kmem_cache_alloc_bulk+0x439/0x950 mm/slub.c:4655
mt_alloc_bulk lib/maple_tree.c:167 [inline]
mas_alloc_nodes+0x39b/0x860 lib/maple_tree.c:1264
mas_node_count_gfp+0x105/0x130 lib/maple_tree.c:1322
mas_preallocate+0x3bb/0x1020 lib/maple_tree.c:5508
vma_iter_prealloc mm/internal.h:1147 [inline]
__split_vma+0x47a/0x1190 mm/mmap.c:2348
split_vma mm/mmap.c:2407 [inline]
vma_modify+0x32a/0x460 mm/mmap.c:2449
vma_modify_flags include/linux/mm.h:3283 [inline]
mprotect_fixup+0x228/0xc90 mm/mprotect.c:635
do_mprotect_pkey+0x860/0xd70 mm/mprotect.c:809
__do_sys_mprotect mm/mprotect.c:830 [inline]
__se_sys_mprotect mm/mprotect.c:827 [inline]
__x64_sys_mprotect+0x78/0xc0 mm/mprotect.c:827

do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6f/0x77

Memory state around the buggy address:

ffff88802a5f2300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802a5f2380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802a5f2400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802a5f2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802a5f2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Tested on:

commit: 7e90b5c2 Merge tag 'trace-tools-v6.8-rc4' of git://git..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

console output: https://syzkaller.appspot.com/x/log.txt?x=15228d14180000

kernel config: https://syzkaller.appspot.com/x/.config?x=df82262440d95bc4
dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=14fc6742180000

[Hillf Danton]

On Tue, 13 Feb 2024 06:08:15 -0800

> HEAD commit: c664e16bb1ba Merge tag 'docs-6.8-fixes2' of git://git.lwn...
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11fcdba2180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

--- x/drivers/gpu/drm/drm_client_modeset.c
+++ y/drivers/gpu/drm/drm_client_modeset.c

@@ -987,6 +987,7 @@ static int drm_client_modeset_commit_ato
struct drm_mode_set *mode_set;
int ret;

+retry:
drm_modeset_acquire_init(&ctx, 0);

state = drm_atomic_state_alloc(dev);
@@ -996,7 +997,6 @@ static int drm_client_modeset_commit_ato
}

state->acquire_ctx = &ctx;
-retry:
drm_for_each_plane(plane, dev) {
struct drm_plane_state *plane_state;

@@ -1051,21 +1051,15 @@ retry:
ret = drm_atomic_commit(state);

out_state:
- if (ret == -EDEADLK)
- goto backoff;
-
drm_atomic_state_put(state);
out_ctx:
drm_modeset_drop_locks(&ctx);
drm_modeset_acquire_fini(&ctx);

- return ret;
-
-backoff:
- drm_atomic_state_clear(state);
- drm_modeset_backoff(&ctx);
+ if (ret == -EDEADLK)
+ goto retry;

- goto retry;
+ return ret;
}

static int drm_client_modeset_commit_legacy(struct drm_client_dev *client)
--

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

stered
[ 7.227065][ T1] io scheduler kyber registered
[ 7.230249][ T1] io scheduler bfq registered
[ 7.274282][ T1] ACPI: \_SB_.GSIE: Enabled at IRQ 20
[ 7.283915][ T1] pcieport 0000:00:04.0: PME: Signaling with IRQ 25
[ 7.291488][ T1] pcieport 0000:00:04.0: AER: enabled with IRQ 26
[ 7.301097][ T1] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input0
[ 7.307815][ T1] ACPI: button: Power Button [PWRF]
[ 7.590815][ T1] ioatdma: Intel(R) QuickData Technology Driver 5.00
[ 7.624170][ T1] ACPI: \_SB_.GSIF: Enabled at IRQ 21
[ 7.661185][ T1] ACPI: \_SB_.GSIH: Enabled at IRQ 23
[ 8.035591][ T1] N_HDLC line discipline registered with maxframe=4096
[ 8.039643][ T1] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 8.046882][ T1] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
[ 8.094343][ T1] Non-volatile memory driver v1.3
[ 8.103986][ T1] Linux agpgart interface v0.103
[ 8.113180][ T1] ACPI: bus type drm_connector registered
[ 8.121142][ T1] [drm] Initialized vgem 1.0.0 20120112 for vgem on minor 0
[ 8.134946][ T1] [drm] Initialized vkms 1.0.0 20180514 for vkms on minor 1
[ 8.237474][ T1] Console: switching to colour frame buffer device 128x48
[ 8.257199][ T1] platform vkms: [drm] fb0: vkmsdrmfb frame buffer device
[ 8.263052][ T1] usbcore: registered new interface driver udl
[ 8.269025][ T1] [drm] pci: virtio-vga detected at 0000:00:01.0
[ 8.274892][ T1] virtio-pci 0000:00:01.0: vgaarb: deactivate vga console
[ 8.283302][ T1] [drm] features: -virgl +edid -resource_blob -host_visible
[ 8.283317][ T1] [drm] features: -context_init
[ 8.301233][ T1] [drm] number of scanouts: 1
[ 8.304828][ T1] [drm] number of cap sets: 0
[ 8.316672][ T1] [drm] Initialized virtio_gpu 0.1.0 0 for 0000:00:01.0 on minor 2
[ 8.382391][ T1] fbcon: virtio_gpudrmfb (fb1) is primary device
[ 8.382410][ T1] fbcon: Remapping primary device, fb1, to tty 1-63
[ 8.400286][ T1] ------------[ cut here ]------------
[ 8.400336][ T1] WARNING: CPU: 0 PID: 1 at drivers/gpu/drm/drm_modeset_lock.c:276 drm_modeset_drop_locks+0x17a/0x210
[ 8.400389][ T1] Modules linked in:
[ 8.400398][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc4-syzkaller-g7e90b5c295ec-dirty #0
[ 8.400408][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 8.400414][ T1] RIP: 0010:drm_modeset_drop_locks+0x17a/0x210
[ 8.400428][ T1] Code: 00 75 39 49 8b 44 24 70 49 39 c5 0f 85 31 ff ff ff 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f e9 cc 75 83 fc e8 c7 75 83 fc 90 <0f> 0b 90 e9 c4 fe ff ff 48 89 df e8 66 9f dc fc eb 9e 4c 89 ef e8
[ 8.400437][ T1] RSP: 0000:ffffc90000047168 EFLAGS: 00010293
[ 8.400447][ T1] RAX: 0000000000000000 RBX: ffffc90000047240 RCX: ffffffff85023ebc
[ 8.400454][ T1] RDX: ffff8880166d8000 RSI: ffffffff8507d859 RDI: ffffc900000472a0
[ 8.400460][ T1] RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
[ 8.400466][ T1] R10: 0000000000000004 R11: 0000000000000009 R12: ffffc90000047240
[ 8.400473][ T1] R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffffffffffdd
[ 8.400483][ T1] FS: 0000000000000000(0000) GS:ffff88806b200000(0000) knlGS:0000000000000000
[ 8.400508][ T1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8.400518][ T1] CR2: ffff88817ffff000 CR3: 000000000d57a000 CR4: 0000000000350ef0
[ 8.400525][ T1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 8.400531][ T1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 8.400537][ T1] Call Trace:
[ 8.400542][ T1] <TASK>
[ 8.400547][ T1] ? show_regs+0x8f/0xa0
[ 8.400561][ T1] ? __warn+0xe6/0x390
[ 8.400575][ T1] ? drm_modeset_drop_locks+0x17a/0x210
[ 8.400587][ T1] ? report_bug+0x3c0/0x580
[ 8.400599][ T1] ? handle_bug+0x3d/0x70
[ 8.400609][ T1] ? exc_invalid_op+0x17/0x50
[ 8.400619][ T1] ? asm_exc_invalid_op+0x1a/0x20
[ 8.400662][ T1] ? drm_dev_put.part.0+0x5c/0x140
[ 8.400676][ T1] ? drm_modeset_drop_locks+0x179/0x210
[ 8.400688][ T1] ? drm_modeset_drop_locks+0x17a/0x210
[ 8.400700][ T1] ? drm_modeset_drop_locks+0x179/0x210
[ 8.400712][ T1] drm_client_modeset_commit_atomic+0x2c2/0x800
[ 8.400726][ T1] ? trace_contention_end+0xda/0x110
[ 8.400739][ T1] ? __pfx_drm_client_modeset_commit_atomic+0x10/0x10
[ 8.400753][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 8.400766][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 8.400780][ T1] ? __pfx___mutex_unlock_slowpath+0x10/0x10
[ 8.400798][ T1] drm_client_modeset_commit_locked+0x14d/0x580
[ 8.400812][ T1] drm_fb_helper_pan_display+0x2a5/0x990
[ 8.400824][ T1] fb_pan_display+0x477/0x7d0
[ 8.400837][ T1] ? __pfx_drm_fb_helper_pan_display+0x10/0x10
[ 8.400848][ T1] bit_update_start+0x49/0x1f0
[ 8.400860][ T1] fbcon_switch+0xbbf/0x12f0
[ 8.400871][ T1] ? __pfx_fbcon_switch+0x10/0x10
[ 8.400882][ T1] ? __pfx_bit_cursor+0x10/0x10
[ 8.400892][ T1] ? fbcon_cursor+0x3e0/0x540
[ 8.400903][ T1] ? is_console_locked+0x9/0x20
[ 8.400913][ T1] ? con_is_visible+0x65/0x150
[ 8.400926][ T1] redraw_screen+0x2bf/0x760
[ 8.400935][ T1] ? __pfx_redraw_screen+0x10/0x10
[ 8.400944][ T1] ? fb_get_color_depth+0x120/0x250
[ 8.400956][ T1] fbcon_prepare_logo+0x9f8/0xc80
[ 8.400968][ T1] set_con2fb_map+0xcf4/0x1060
[ 8.400979][ T1] fbcon_fb_registered+0x21d/0x670
[ 8.400990][ T1] ? fb_var_to_videomode+0x4c9/0x690
[ 8.401003][ T1] register_framebuffer+0x4b2/0x860
[ 8.401015][ T1] ? __pfx_register_framebuffer+0x10/0x10
[ 8.401028][ T1] ? drm_fbdev_generic_helper_fb_probe+0x4e2/0x6d0
[ 8.401038][ T1] __drm_fb_helper_initial_config_and_unlock+0xd82/0x1650
[ 8.401051][ T1] ? __pfx___drm_fb_helper_initial_config_and_unlock+0x10/0x10
[ 8.401064][ T1] drm_fb_helper_initial_config+0x44/0x60
[ 8.401075][ T1] drm_fbdev_generic_client_hotplug+0x1a6/0x280
[ 8.401085][ T1] ? __pfx_drm_fbdev_generic_client_hotplug+0x10/0x10
[ 8.401095][ T1] drm_client_register+0x195/0x280
[ 8.401107][ T1] drm_fbdev_generic_setup+0x184/0x340
[ 8.401118][ T1] virtio_gpu_probe+0x29d/0x4e0
[ 8.401131][ T1] virtio_dev_probe+0x5ff/0x9b0
[ 8.401142][ T1] ? __pfx_virtio_dev_probe+0x10/0x10
[ 8.401151][ T1] really_probe+0x23a/0xcb0
[ 8.401165][ T1] __driver_probe_device+0x1de/0x4b0
[ 8.401174][ T1] ? _raw_spin_unlock_irqrestore+0x52/0x80
[ 8.401187][ T1] driver_probe_device+0x4c/0x1b0
[ 8.401196][ T1] __driver_attach+0x283/0x580
[ 8.401204][ T1] ? __pfx___driver_attach+0x10/0x10
[ 8.401213][ T1] bus_for_each_dev+0x13c/0x1d0
[ 8.401225][ T1] ? __pfx_bus_for_each_dev+0x10/0x10
[ 8.401237][ T1] bus_add_driver+0x2ed/0x640
[ 8.401250][ T1] ? __pfx_virtio_gpu_driver_init+0x10/0x10
[ 8.401263][ T1] driver_register+0x15c/0x4b0
[ 8.401273][ T1] do_one_initcall+0x11c/0x670
[ 8.401286][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 8.401299][ T1] ? trace_kmalloc+0x2e/0xb0
[ 8.401313][ T1] ? __kmalloc+0x218/0x440
[ 8.401323][ T1] kernel_init_freeable+0x68d/0xc10
[ 8.401338][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.401349][ T1] kernel_init+0x1c/0x2a0
[ 8.401359][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.401370][ T1] ret_from_fork+0x45/0x80
[ 8.401383][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.401393][ T1] ret_from_fork_asm+0x1b/0x30
[ 8.401407][ T1] </TASK>
[ 8.401412][ T1] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 8.401417][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc4-syzkaller-g7e90b5c295ec-dirty #0
[ 8.401426][ T1] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 8.401430][ T1] Call Trace:
[ 8.401433][ T1] <TASK>
[ 8.401436][ T1] dump_stack_lvl+0xd9/0x1b0
[ 8.401447][ T1] panic+0x6ee/0x7a0
[ 8.401458][ T1] ? __pfx_panic+0x10/0x10
[ 8.401469][ T1] ? show_trace_log_lvl+0x363/0x500
[ 8.401482][ T1] ? check_panic_on_warn+0x1f/0xb0
[ 8.401493][ T1] ? drm_modeset_drop_locks+0x17a/0x210
[ 8.401504][ T1] check_panic_on_warn+0xab/0xb0
[ 8.401516][ T1] __warn+0xf2/0x390
[ 8.401527][ T1] ? drm_modeset_drop_locks+0x17a/0x210
[ 8.401538][ T1] report_bug+0x3c0/0x580
[ 8.401547][ T1] handle_bug+0x3d/0x70
[ 8.401556][ T1] exc_invalid_op+0x17/0x50
[ 8.401565][ T1] asm_exc_invalid_op+0x1a/0x20
[ 8.401576][ T1] RIP: 0010:drm_modeset_drop_locks+0x17a/0x210
[ 8.401587][ T1] Code: 00 75 39 49 8b 44 24 70 49 39 c5 0f 85 31 ff ff ff 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f e9 cc 75 83 fc e8 c7 75 83 fc 90 <0f> 0b 90 e9 c4 fe ff ff 48 89 df e8 66 9f dc fc eb 9e 4c 89 ef e8
[ 8.401595][ T1] RSP: 0000:ffffc90000047168 EFLAGS: 00010293
[ 8.401602][ T1] RAX: 0000000000000000 RBX: ffffc90000047240 RCX: ffffffff85023ebc
[ 8.401607][ T1] RDX: ffff8880166d8000 RSI: ffffffff8507d859 RDI: ffffc900000472a0
[ 8.401612][ T1] RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
[ 8.401617][ T1] R10: 0000000000000004 R11: 0000000000000009 R12: ffffc90000047240
[ 8.401622][ T1] R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffffffffffdd
[ 8.401628][ T1] ? drm_dev_put.part.0+0x5c/0x140
[ 8.401640][ T1] ? drm_modeset_drop_locks+0x179/0x210
[ 8.401651][ T1] ? drm_modeset_drop_locks+0x179/0x210
[ 8.401662][ T1] drm_client_modeset_commit_atomic+0x2c2/0x800
[ 8.401674][ T1] ? trace_contention_end+0xda/0x110
[ 8.401685][ T1] ? __pfx_drm_client_modeset_commit_atomic+0x10/0x10
[ 8.401697][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 8.401709][ T1] ? __mutex_lock+0x1a6/0x9d0
[ 8.401721][ T1] ? __pfx___mutex_unlock_slowpath+0x10/0x10
[ 8.401734][ T1] drm_client_modeset_commit_locked+0x14d/0x580
[ 8.401746][ T1] drm_fb_helper_pan_display+0x2a5/0x990
[ 8.401756][ T1] fb_pan_display+0x477/0x7d0
[ 8.401766][ T1] ? __pfx_drm_fb_helper_pan_display+0x10/0x10
[ 8.401776][ T1] bit_update_start+0x49/0x1f0
[ 8.401786][ T1] fbcon_switch+0xbbf/0x12f0
[ 8.401799][ T1] ? __pfx_fbcon_switch+0x10/0x10
[ 8.401808][ T1] ? __pfx_bit_cursor+0x10/0x10
[ 8.401818][ T1] ? fbcon_cursor+0x3e0/0x540
[ 8.401827][ T1] ? is_console_locked+0x9/0x20
[ 8.401836][ T1] ? con_is_visible+0x65/0x150
[ 8.401847][ T1] redraw_screen+0x2bf/0x760
[ 8.401854][ T1] ? __pfx_redraw_screen+0x10/0x10
[ 8.401862][ T1] ? fb_get_color_depth+0x120/0x250
[ 8.401873][ T1] fbcon_prepare_logo+0x9f8/0xc80
[ 8.401883][ T1] set_con2fb_map+0xcf4/0x1060
[ 8.401893][ T1] fbcon_fb_registered+0x21d/0x670
[ 8.401902][ T1] ? fb_var_to_videomode+0x4c9/0x690
[ 8.401914][ T1] register_framebuffer+0x4b2/0x860
[ 8.401925][ T1] ? __pfx_register_framebuffer+0x10/0x10
[ 8.401936][ T1] ? drm_fbdev_generic_helper_fb_probe+0x4e2/0x6d0
[ 8.401945][ T1] __drm_fb_helper_initial_config_and_unlock+0xd82/0x1650
[ 8.401956][ T1] ? __pfx___drm_fb_helper_initial_config_and_unlock+0x10/0x10
[ 8.401968][ T1] drm_fb_helper_initial_config+0x44/0x60
[ 8.401977][ T1] drm_fbdev_generic_client_hotplug+0x1a6/0x280
[ 8.401986][ T1] ? __pfx_drm_fbdev_generic_client_hotplug+0x10/0x10
[ 8.401994][ T1] drm_client_register+0x195/0x280
[ 8.402005][ T1] drm_fbdev_generic_setup+0x184/0x340
[ 8.402014][ T1] virtio_gpu_probe+0x29d/0x4e0
[ 8.402025][ T1] virtio_dev_probe+0x5ff/0x9b0
[ 8.402033][ T1] ? __pfx_virtio_dev_probe+0x10/0x10
[ 8.402041][ T1] really_probe+0x23a/0xcb0
[ 8.402053][ T1] __driver_probe_device+0x1de/0x4b0
[ 8.402061][ T1] ? _raw_spin_unlock_irqrestore+0x52/0x80
[ 8.402072][ T1] driver_probe_device+0x4c/0x1b0
[ 8.402080][ T1] __driver_attach+0x283/0x580
[ 8.402088][ T1] ? __pfx___driver_attach+0x10/0x10
[ 8.402095][ T1] bus_for_each_dev+0x13c/0x1d0
[ 8.402106][ T1] ? __pfx_bus_for_each_dev+0x10/0x10
[ 8.402116][ T1] bus_add_driver+0x2ed/0x640
[ 8.402128][ T1] ? __pfx_virtio_gpu_driver_init+0x10/0x10
[ 8.402138][ T1] driver_register+0x15c/0x4b0
[ 8.402147][ T1] do_one_initcall+0x11c/0x670
[ 8.402158][ T1] ? __pfx_do_one_initcall+0x10/0x10
[ 8.402169][ T1] ? trace_kmalloc+0x2e/0xb0
[ 8.402181][ T1] ? __kmalloc+0x218/0x440
[ 8.402190][ T1] kernel_init_freeable+0x68d/0xc10
[ 8.402203][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.402212][ T1] kernel_init+0x1c/0x2a0
[ 8.402221][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.402230][ T1] ret_from_fork+0x45/0x80
[ 8.402241][ T1] ? __pfx_kernel_init+0x10/0x10
[ 8.402251][ T1] ret_from_fork_asm+0x1b/0x30
[ 8.402263][ T1] </TASK>
[ 8.403059][ T1] Kernel Offset: disabled

GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build253358196=/tmp/go-build -gno-record-gcc-switches"

git status (err=<nil>)
HEAD detached at e66542d78
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:32: run command via tools/syz-env for best compatibility, see:
Makefile:33: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' ./sys/syz-sysgen | grep -q false || go install ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=e66542d78f1cf0c783877440cd239a11fb73fb15 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240213-111349'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-fuzzer github.com/google/syzkaller/syz-fuzzer
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=e66542d78f1cf0c783877440cd239a11fb73fb15 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240213-111349'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=e66542d78f1cf0c783877440cd239a11fb73fb15 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20240213-111349'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-stress github.com/google/syzkaller/tools/syz-stress
mkdir -p ./bin/linux_amd64
gcc -o ./bin/linux_amd64/syz-executor executor/executor.cc \
-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w -DGOOS_linux=1 -DGOARCH_amd64=1 \
-DHOSTGOOS_linux=1 -DGIT_REVISION=\"e66542d78f1cf0c783877440cd239a11fb73fb15\"


Error text is too large and was truncated, full error text is at:

https://syzkaller.appspot.com/x/error.txt?x=1395d592180000

Tested on:

commit: 7e90b5c2 Merge tag 'trace-tools-v6.8-rc4' of git://git..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

kernel config: https://syzkaller.appspot.com/x/.config?x=df82262440d95bc4
dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1247ec62180000

[Hillf Danton]

On Tue, 13 Feb 2024 06:08:15 -0800

> HEAD commit: c664e16bb1ba Merge tag 'docs-6.8-fixes2' of git://git.lwn...
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11fcdba2180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

--- x/drivers/gpu/drm/drm_atomic_helper.c
+++ y/drivers/gpu/drm/drm_atomic_helper.c
@@ -1849,7 +1849,11 @@ static void commit_work(struct work_stru
struct drm_atomic_state *state = container_of(work,
struct drm_atomic_state,
commit_work);
+ struct drm_device *dev = state->dev;
+
+ mutex_lock(&dev->master_mutex);
commit_tail(state);
+ mutex_unlock(&dev->master_mutex);
}

/**
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+0f999d...@syzkaller.appspotmail.com

Tested on:

commit: 7e90b5c2 Merge tag 'trace-tools-v6.8-rc4' of git://git..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

console output: https://syzkaller.appspot.com/x/log.txt?x=1790f698180000

kernel config: https://syzkaller.appspot.com/x/.config?x=df82262440d95bc4
dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=12fa241c180000

Note: testing is done by a robot and is best-effort only.

[Edward Adam Davis]

please test uaf in drm_atomic_helper_wait_for_vblanks

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 39ef0a6addeb..b16ff9020097 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1743,7 +1743,9 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_flip_done);
void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
{
struct drm_device *dev = old_state->dev;
+ static DEFINE_MUTEX(lock);

+ mutex_lock(&lock);
drm_atomic_helper_commit_modeset_disables(dev, old_state);

drm_atomic_helper_commit_planes(dev, old_state, 0);
@@ -1757,6 +1759,7 @@ void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
drm_atomic_helper_wait_for_vblanks(dev, old_state);

drm_atomic_helper_cleanup_planes(dev, old_state);
+ mutex_unlock(&lock);
}
EXPORT_SYMBOL(drm_atomic_helper_commit_tail);

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+0f999d...@syzkaller.appspotmail.com

Tested on:

commit: 8d3dea21 Merge tag 'mips-fixes_6.8_2' of git://git.ker..

git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

console output: https://syzkaller.appspot.com/x/log.txt?x=161f04d0180000

kernel config: https://syzkaller.appspot.com/x/.config?x=df82262440d95bc4
dashboard link: https://syzkaller.appspot.com/bug?extid=0f999d26a4fd79c3a23b
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=167a4410180000

[Edward Adam Davis]

To briefly summarize the issues reported by syzbot, there are two task call stacks
as follows:

Task A Task B
------------------------------------ ----------------------------------
drm_atomic_nonblocking_commit drm_atomic_commit
drm_atomic_helper_commit drm_atomic_helper_commit
commit_work
commit_tail
drm_atomic_helper_commit_tail commit_tail
drm_atomic_helper_commit_tail
drm_client_modeset_commit_atomic
drm_atomic_state_default_clear
drm_atomic_helper_wait_for_vblanks

When two prerequisites are met simultaneously, the current issue will be triggered:
1. There is an overlap in the memory range occupied by the crtcs member set contained
in the instance state of "struct drm_atomic_state" created by Task A and Task B
2. The context of drm_atomic_helper_commit_tail() has no lock protection, resulting
in the instance state->crtcs sub item being released by other task

The solution is to add a lock in drm_atomic_helper_commit_tail() to ensure that
there is no other task interference when accessing the instance state.

Reported-and-tested-by: syzbot+0f999d...@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <ead...@qq.com>
---
drivers/gpu/drm/drm_atomic_helper.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 39ef0a6addeb..b16ff9020097 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1743,7 +1743,9 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_flip_done);
void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
{
struct drm_device *dev = old_state->dev;
+ static DEFINE_MUTEX(lock);

+ mutex_lock(&lock);
drm_atomic_helper_commit_modeset_disables(dev, old_state);

drm_atomic_helper_commit_planes(dev, old_state, 0);
@@ -1757,6 +1759,7 @@ void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
drm_atomic_helper_wait_for_vblanks(dev, old_state);

drm_atomic_helper_cleanup_planes(dev, old_state);
+ mutex_unlock(&lock);
}
EXPORT_SYMBOL(drm_atomic_helper_commit_tail);

--
2.43.0

[Edward Adam Davis]

To briefly summarize the issues reported by syzbot, there are two task call stacks
as follows:

Task A Task B
------------------------------------ ----------------------------------

drm_atomic_commit