[syzbot] [bcachefs?] KASAN: slab-use-after-free Read in bch2_get_next_online_dev

From: syzbot
Date: Mon Nov 11 2024 - 04:39:38 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 6c52d4da1c74 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=173eb2a7980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4aec7739e14231a7
dashboard link: https://syzkaller.appspot.com/bug?extid=847360a3270f2e7712f9
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e65174ffb5e3/disk-6c52d4da.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/862551e30b0d/vmlinux-6c52d4da.xz
kernel image: https://storage.googleapis.com/syzbot-assets/78464001f495/bzImage-6c52d4da.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+847360a3270f2e7712f9@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: slab-use-after-free in bch2_get_next_online_dev+0x369/0x4d0 fs/bcachefs/sb-members.h:154
Read of size 1 at addr ffff88805934213e by task kworker/u9:1/5144

CPU: 0 UID: 0 PID: 5144 Comm: kworker/u9:1 Not tainted 6.12.0-rc5-syzkaller-00181-g6c52d4da1c74 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: bcachefs_journal bch2_journal_write
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
bch2_get_next_online_dev+0x369/0x4d0 fs/bcachefs/sb-members.h:154
bch2_journal_write+0x158/0x4860 fs/bcachefs/journal_io.c:1982
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Allocated by task 14451:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:257 [inline]
__kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4295
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
__bch2_dev_alloc+0x57/0xa60 fs/bcachefs/super.c:1303
bch2_dev_alloc+0xd4/0x170 fs/bcachefs/super.c:1373
bch2_fs_alloc fs/bcachefs/super.c:938 [inline]
bch2_fs_open+0x2e3f/0x2f80 fs/bcachefs/super.c:2064
bch2_fs_get_tree+0x738/0x1710 fs/bcachefs/fs.c:2157
vfs_get_tree+0x92/0x2b0 fs/super.c:1800
do_new_mount+0x2be/0xb40 fs/namespace.c:3507
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13670:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:2342 [inline]
slab_free mm/slub.c:4579 [inline]
kfree+0x1a0/0x440 mm/slub.c:4727
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x231/0x480 lib/kobject.c:737
bch2_fs_free+0x27b/0x3c0 fs/bcachefs/super.c:666
deactivate_locked_super+0xc6/0x130 fs/super.c:473
cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
task_work_run+0x251/0x310 kernel/task_work.c:239
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
insert_work+0x3e/0x330 kernel/workqueue.c:2183
__queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
queue_work include/linux/workqueue.h:662 [inline]
bch2_dev_do_discards+0x17a/0x1f0 fs/bcachefs/alloc_background.c:1912
bch2_do_discards+0x29/0x60 fs/bcachefs/alloc_background.c:1923
journal_write_done+0x785/0xea0 fs/bcachefs/journal_io.c:1620
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Second to last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
insert_work+0x3e/0x330 kernel/workqueue.c:2183
__queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
queue_work include/linux/workqueue.h:662 [inline]
bch2_dev_do_invalidates+0x17a/0x1f0 fs/bcachefs/alloc_background.c:2171
bch2_do_invalidates+0x29/0x60 fs/bcachefs/alloc_background.c:2182
__bch2_fs_read_write+0x34c/0x370 fs/bcachefs/super.c:499
bch2_run_recovery_pass+0xf2/0x1e0 fs/bcachefs/recovery_passes.c:185
bch2_run_recovery_passes+0x387/0x870 fs/bcachefs/recovery_passes.c:232
bch2_fs_recovery+0x25cc/0x39c0 fs/bcachefs/recovery.c:862
bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1036
bch2_fs_get_tree+0xd68/0x1710 fs/bcachefs/fs.c:2170
vfs_get_tree+0x92/0x2b0 fs/super.c:1800
do_new_mount+0x2be/0xb40 fs/namespace.c:3507
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888059342000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 318 bytes inside of
freed 4096-byte region [ffff888059342000, ffff888059343000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x59340
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801ac42140 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000040004 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff88801ac42140 0000000000000000 dead000000000001
head: 0000000000000000 0000000000040004 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea000164d001 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5936, tgid 5936 (kworker/u8:8), ts 311583359383, free_ts 302863591566
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537
prep_new_page mm/page_alloc.c:1545 [inline]
get_page_from_freelist+0x303f/0x3190 mm/page_alloc.c:3457
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4733
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x120 mm/slub.c:2412
allocate_slab+0x5a/0x2f0 mm/slub.c:2578
new_slab mm/slub.c:2631 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3818
__slab_alloc+0x58/0xa0 mm/slub.c:3908
__slab_alloc_node mm/slub.c:3961 [inline]
slab_alloc_node mm/slub.c:4122 [inline]
__do_kmalloc_node mm/slub.c:4263 [inline]
__kmalloc_node_track_caller_noprof+0x281/0x440 mm/slub.c:4283
kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:609
__alloc_skb+0x1f3/0x440 net/core/skbuff.c:678
alloc_skb include/linux/skbuff.h:1322 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
nsim_dev_trap_report_work+0x254/0xab0 drivers/net/netdevsim/dev.c:851
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
page last free pid 5207 tgid 5207 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1108 [inline]
free_unref_page+0xcfb/0xf20 mm/page_alloc.c:2638
discard_slab mm/slub.c:2677 [inline]
__put_partials+0xeb/0x130 mm/slub.c:3145
put_cpu_partial+0x17c/0x250 mm/slub.c:3220
__slab_free+0x2ea/0x3d0 mm/slub.c:4449
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:247 [inline]
slab_post_alloc_hook mm/slub.c:4085 [inline]
slab_alloc_node mm/slub.c:4134 [inline]
__kmalloc_cache_noprof+0x132/0x2c0 mm/slub.c:4290
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
kernfs_fop_open+0x3e0/0xd10 fs/kernfs/file.c:623
do_dentry_open+0x97a/0x1460 fs/open.c:958
vfs_open+0x3e/0x330 fs/open.c:1088
do_open fs/namei.c:3774 [inline]
path_openat+0x2c84/0x3590 fs/namei.c:3933
do_filp_open+0x235/0x490 fs/namei.c:3960
do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
do_sys_open fs/open.c:1430 [inline]
__do_sys_openat fs/open.c:1446 [inline]
__se_sys_openat fs/open.c:1441 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1441
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83

Memory state around the buggy address:
ffff888059342000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888059342080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888059342100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888059342180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888059342200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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