[moderation] [io-uring?] KASAN: slab-use-after-free Read in io_poll_remove_entries

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 155a3c003e55 Merge tag 'for-6.16/dm-fixes-2' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14d38382580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5ae63460f9c371aa
dashboard link: https://syzkaller.appspot.com/bug?extid=6e6f1109f10ea0096778
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
CC: [ax...@kernel.dk io-u...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dcbbac96d733/disk-155a3c00.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eec589968921/vmlinux-155a3c00.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80e95076a622/bzImage-155a3c00.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6e6f11...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170
Read of size 1 at addr ffff88807555f8b0 by task syz.5.6164/27259

CPU: 0 UID: 0 PID: 27259 Comm: syz.5.6164 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcd/0x610 mm/kasan/report.c:480
kasan_report+0xe0/0x110 mm/kasan/report.c:593
__kasan_check_byte+0x36/0x50 mm/kasan/common.c:557
kasan_check_byte include/linux/kasan.h:399 [inline]
lock_acquire kernel/locking/lockdep.c:5845 [inline]
lock_acquire+0xfc/0x350 kernel/locking/lockdep.c:5828
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
_raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170
spin_lock_irq include/linux/spinlock.h:376 [inline]
io_poll_remove_entry io_uring/poll.c:146 [inline]
io_poll_remove_entries.part.0+0x14e/0x7e0 io_uring/poll.c:179
io_poll_remove_entries io_uring/poll.c:159 [inline]
io_poll_task_func+0x65d/0x1240 io_uring/poll.c:328
io_handle_tw_list+0x155/0x500 io_uring/io_uring.c:1067
tctx_task_work_run+0xac/0x380 io_uring/io_uring.c:1132
tctx_task_work+0x7a/0xd0 io_uring/io_uring.c:1150
task_work_run+0x14d/0x240 kernel/task_work.c:227
get_signal+0x1d1/0x26d0 kernel/signal.c:2807
arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f611bf8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f611cd6e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f611c1b5fa0 RCX: 00007f611bf8e929
RDX: 0000000000000000 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007f611c010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f611c1b5fa0 R15: 00007ffe23dec618
</TASK>

Allocated by task 19567:
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:377 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
__comedi_device_postconfig_async drivers/comedi/drivers.c:664 [inline]
__comedi_device_postconfig drivers/comedi/drivers.c:721 [inline]
comedi_device_postconfig+0x2cb/0xc80 drivers/comedi/drivers.c:756
comedi_device_attach+0x3cf/0x900 drivers/comedi/drivers.c:998
do_devconfig_ioctl+0x1a7/0x580 drivers/comedi/comedi_fops.c:855
comedi_unlocked_ioctl+0x15bb/0x2e90 drivers/comedi/comedi_fops.c:2136
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 27259:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2381 [inline]
slab_free mm/slub.c:4643 [inline]
kfree+0x2b4/0x4d0 mm/slub.c:4842
comedi_device_detach_cleanup drivers/comedi/drivers.c:171 [inline]
comedi_device_detach+0x2a4/0x9e0 drivers/comedi/drivers.c:208
do_devconfig_ioctl+0x46c/0x580 drivers/comedi/comedi_fops.c:833
comedi_unlocked_ioctl+0x15bb/0x2e90 drivers/comedi/comedi_fops.c:2136
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807555f800
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 176 bytes inside of
freed 256-byte region [ffff88807555f800, ffff88807555f900)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807555e000 pfn:0x7555e
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801b841b40 ffffea00017f8c90 ffffea00009c7910
raw: ffff88807555e000 0000000000100004 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b841b40 ffffea00017f8c90 ffffea00009c7910
head: ffff88807555e000 0000000000100004 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0001d55781 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5842, tgid 5842 (syz-executor), ts 71675200951, free_ts 71628382950
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
prep_new_page mm/page_alloc.c:1712 [inline]
get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
__alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
alloc_slab_page mm/slub.c:2451 [inline]
allocate_slab mm/slub.c:2619 [inline]
new_slab+0x23b/0x330 mm/slub.c:2673
___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
__slab_alloc_node mm/slub.c:4024 [inline]
slab_alloc_node mm/slub.c:4185 [inline]
__do_kmalloc_node mm/slub.c:4327 [inline]
__kmalloc_noprof+0x2f2/0x510 mm/slub.c:4340
kmalloc_noprof include/linux/slab.h:909 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
fib_create_info+0x53f/0x46b0 net/ipv4/fib_semantics.c:1407
fib_table_insert+0x177/0x1c40 net/ipv4/fib_trie.c:1212
fib_magic+0x4d4/0x5c0 net/ipv4/fib_frontend.c:1133
fib_add_ifaddr+0x16d/0x580 net/ipv4/fib_frontend.c:1155
fib_inetaddr_event+0x147/0x270 net/ipv4/fib_frontend.c:1469
notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
blocking_notifier_call_chain kernel/notifier.c:380 [inline]
blocking_notifier_call_chain+0x69/0xa0 kernel/notifier.c:368
__inet_insert_ifa+0x925/0xcd0 net/ipv4/devinet.c:567
page last free pid 5839 tgid 5839 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1248 [inline]
__free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4148 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
__kmalloc_cache_noprof+0x1f1/0x3e0 mm/slub.c:4354
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
____ip_mc_inc_group+0x403/0x10f0 net/ipv4/igmp.c:1535
__ip_mc_inc_group net/ipv4/igmp.c:1573 [inline]
ip_mc_inc_group net/ipv4/igmp.c:1579 [inline]
ip_mc_up+0x154/0x3b0 net/ipv4/igmp.c:1880
inetdev_event+0xafb/0x18a0 net/ipv4/devinet.c:1631
notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
__dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9497
netif_change_flags+0x108/0x160 net/core/dev.c:9526
do_setlink.constprop.0+0xb53/0x4380 net/core/rtnetlink.c:3141
rtnl_changelink net/core/rtnetlink.c:3759 [inline]
__rtnl_newlink net/core/rtnetlink.c:3918 [inline]
rtnl_newlink+0x1446/0x2000 net/core/rtnetlink.c:4055
rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6944
netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552

Memory state around the buggy address:
ffff88807555f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807555f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807555f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807555f900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807555f980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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