[syzbot] [xfs?] KASAN: slab-use-after-free Read in iomap_finish_ioend

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Apr 13, 2023, 4:03:22 AM4/13/23
to djw...@kernel.org, h...@infradead.org, linux-...@vger.kernel.org, linux-...@vger.kernel.org, linu...@vger.kernel.org, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: a79d5c76f705 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10e54345c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=5666fa6aca264e42
dashboard link: https://syzkaller.appspot.com/bug?extid=9c656068e71c1b06dc1f
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/adf61ecd5810/disk-a79d5c76.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8192876ea15a/vmlinux-a79d5c76.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80c6e54ddbe7/bzImage-a79d5c76.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9c6560...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in iomap_finish_ioend+0x8a4/0x960 fs/iomap/buffered-io.c:1353
Read of size 8 at addr ffff88807925b090 by task kworker/1:0/22

CPU: 1 PID: 22 Comm: kworker/1:0 Not tainted 6.3.0-rc5-syzkaller-00202-ga79d5c76f705 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Workqueue: xfs-conv/loop2 xfs_end_io
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:319 [inline]
print_report+0x163/0x540 mm/kasan/report.c:430
kasan_report+0x176/0x1b0 mm/kasan/report.c:536
iomap_finish_ioend+0x8a4/0x960 fs/iomap/buffered-io.c:1353
iomap_finish_ioends+0x1af/0x3a0 fs/iomap/buffered-io.c:1377
xfs_end_ioend+0x36e/0x4d0 fs/xfs/xfs_aops.c:136
xfs_end_io+0x2e5/0x370 fs/xfs/xfs_aops.c:173
process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2390
worker_thread+0xa63/0x1210 kernel/workqueue.c:2537
kthread+0x270/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>

Allocated by task 12928:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x66/0x70 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:186 [inline]
slab_post_alloc_hook+0x68/0x3a0 mm/slab.h:769
slab_alloc_node mm/slub.c:3452 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc_lru+0x11f/0x2e0 mm/slub.c:3483
alloc_inode_sb include/linux/fs.h:2686 [inline]
xfs_inode_alloc+0x88/0x6c0 fs/xfs/xfs_icache.c:81
xfs_iget_cache_miss fs/xfs/xfs_icache.c:585 [inline]
xfs_iget+0xad2/0x2fd0 fs/xfs/xfs_icache.c:751
xfs_init_new_inode+0x1ca/0x10a0 fs/xfs/xfs_inode.c:815
xfs_create+0x8ce/0x1240 fs/xfs/xfs_inode.c:1023
xfs_generic_create+0x491/0xd70 fs/xfs/xfs_iops.c:199
lookup_open fs/namei.c:3416 [inline]
open_last_lookups fs/namei.c:3484 [inline]
path_openat+0x13df/0x3170 fs/namei.c:3712
do_filp_open+0x234/0x490 fs/namei.c:3742
do_sys_openat2+0x13f/0x500 fs/open.c:1348
do_sys_open fs/open.c:1364 [inline]
__do_sys_openat fs/open.c:1380 [inline]
__se_sys_openat fs/open.c:1375 [inline]
__x64_sys_openat+0x247/0x290 fs/open.c:1375
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 15:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:521
____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:162 [inline]
slab_free_hook mm/slub.c:1781 [inline]
slab_free_freelist_hook mm/slub.c:1807 [inline]
slab_free mm/slub.c:3787 [inline]
kmem_cache_free+0x297/0x520 mm/slub.c:3809
rcu_do_batch kernel/rcu/tree.c:2112 [inline]
rcu_core+0xa4d/0x16f0 kernel/rcu/tree.c:2372
__do_softirq+0x2ab/0x908 kernel/softirq.c:571

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:491
__call_rcu_common kernel/rcu/tree.c:2622 [inline]
call_rcu+0x167/0xa70 kernel/rcu/tree.c:2736
__xfs_inode_free fs/xfs/xfs_icache.c:161 [inline]
xfs_reclaim_inode fs/xfs/xfs_icache.c:953 [inline]
xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1635 [inline]
xfs_icwalk_ag+0x1366/0x1a60 fs/xfs/xfs_icache.c:1717
xfs_icwalk fs/xfs/xfs_icache.c:1766 [inline]
xfs_reclaim_inodes+0x1f7/0x310 fs/xfs/xfs_icache.c:986
xfs_unmount_flush_inodes+0xaf/0xc0 fs/xfs/xfs_mount.c:594
xfs_unmountfs+0xc4/0x280 fs/xfs/xfs_mount.c:1071
xfs_fs_put_super+0x74/0x2d0 fs/xfs/xfs_super.c:1126
generic_shutdown_super+0x134/0x340 fs/super.c:500
kill_block_super+0x7e/0xe0 fs/super.c:1407
deactivate_locked_super+0xa4/0x110 fs/super.c:331
cleanup_mnt+0x426/0x4c0 fs/namespace.c:1177
task_work_run+0x24a/0x300 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:297
do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:491
insert_work+0x54/0x3d0 kernel/workqueue.c:1361
__queue_work+0xb37/0xf10 kernel/workqueue.c:1524
queue_work_on+0x14f/0x250 kernel/workqueue.c:1552
queue_work include/linux/workqueue.h:504 [inline]
xfs_end_bio+0xf6/0x1e0 fs/xfs/xfs_aops.c:188
req_bio_endio block/blk-mq.c:795 [inline]
blk_update_request+0x4d7/0xfe0 block/blk-mq.c:927
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1054
blk_complete_reqs block/blk-mq.c:1132 [inline]
blk_done_softirq+0xfc/0x150 block/blk-mq.c:1137
__do_softirq+0x2ab/0x908 kernel/softirq.c:571

The buggy address belongs to the object at ffff88807925ae80
which belongs to the cache xfs_inode of size 1808
The buggy address is located 528 bytes inside of
freed 1808-byte region [ffff88807925ae80, ffff88807925b590)

The buggy address belongs to the physical page:
page:ffffea0001e49600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79258
head:ffffea0001e49600 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888034708001
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff888145f6e780 ffffea0000ecce00 dead000000000002
raw: 0000000000000000 0000000080100010 00000001ffffffff ffff888034708001
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 30191, tgid 30185 (syz-executor.2), ts 2829909820429, free_ts 2816156356992
prep_new_page mm/page_alloc.c:2553 [inline]
get_page_from_freelist+0x3246/0x33c0 mm/page_alloc.c:4326
__alloc_pages+0x255/0x670 mm/page_alloc.c:5592
alloc_slab_page+0x6a/0x160 mm/slub.c:1851
allocate_slab mm/slub.c:1998 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2051
___slab_alloc+0xa85/0x10a0 mm/slub.c:3193
__slab_alloc mm/slub.c:3292 [inline]
__slab_alloc_node mm/slub.c:3345 [inline]
slab_alloc_node mm/slub.c:3442 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc_lru+0x1b9/0x2e0 mm/slub.c:3483
alloc_inode_sb include/linux/fs.h:2686 [inline]
xfs_inode_alloc+0x88/0x6c0 fs/xfs/xfs_icache.c:81
xfs_iget_cache_miss fs/xfs/xfs_icache.c:585 [inline]
xfs_iget+0xad2/0x2fd0 fs/xfs/xfs_icache.c:751
xfs_init_new_inode+0x1ca/0x10a0 fs/xfs/xfs_inode.c:815
xfs_symlink+0xb7b/0x1e80 fs/xfs/xfs_symlink.c:234
xfs_vn_symlink+0x1f5/0x740 fs/xfs/xfs_iops.c:419
vfs_symlink+0x12f/0x2a0 fs/namei.c:4398
do_symlinkat+0x201/0x610 fs/namei.c:4424
__do_sys_symlink fs/namei.c:4445 [inline]
__se_sys_symlink fs/namei.c:4443 [inline]
__x64_sys_symlink+0x7e/0x90 fs/namei.c:4443
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1454 [inline]
free_pcp_prepare mm/page_alloc.c:1504 [inline]
free_unref_page_prepare+0xe2f/0xe70 mm/page_alloc.c:3388
free_unref_page+0x37/0x3f0 mm/page_alloc.c:3483
qlist_free_all+0x22/0x60 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x14b/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x23/0x70 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:186 [inline]
slab_post_alloc_hook+0x68/0x3a0 mm/slab.h:769
slab_alloc_node mm/slub.c:3452 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc+0x11f/0x2e0 mm/slub.c:3476
getname_flags+0xbc/0x4e0 fs/namei.c:140
do_sys_openat2+0xd6/0x500 fs/open.c:1342
do_sys_open fs/open.c:1364 [inline]
__do_sys_open fs/open.c:1372 [inline]
__se_sys_open fs/open.c:1368 [inline]
__x64_sys_open+0x225/0x270 fs/open.c:1368
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff88807925af80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807925b000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807925b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807925b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807925b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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syzbot

unread,
Aug 7, 2023, 3:45:37 AM8/7/23
to syzkall...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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