[syzbot] [fs?] KASAN: slab-use-after-free Read in sys_io_cancel

From: syzbot
Date: Sun Mar 03 2024 - 02:29:37 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 5ad3cb0ed525 Merge tag 'for-v6.8-rc2' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16e39306180000
kernel config: https://syzkaller.appspot.com/x/.config?x=fad652894fc96962
dashboard link: https://syzkaller.appspot.com/bug?extid=b91eb2ed18f599dd3c31
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=149defac180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13877412180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/16eec3abf3df/disk-5ad3cb0e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3a72615a6fd4/vmlinux-5ad3cb0e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6f728d92d6c1/bzImage-5ad3cb0e.xz

The issue was bisected to:

commit 54cbc058d86beca3515c994039b5c0f0a34f53dd
Author: Bart Van Assche <bvanassche@xxxxxxx>
Date: Thu Feb 15 20:47:39 2024 +0000

fs/aio: Make io_cancel() generate completions again

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1748740e180000
final oops: https://syzkaller.appspot.com/x/report.txt?x=14c8740e180000
console output: https://syzkaller.appspot.com/x/log.txt?x=10c8740e180000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b91eb2ed18f599dd3c31@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 54cbc058d86b ("fs/aio: Make io_cancel() generate completions again")

==================================================================
BUG: KASAN: slab-use-after-free in __do_sys_io_cancel fs/aio.c:2207 [inline]
BUG: KASAN: slab-use-after-free in __se_sys_io_cancel+0x2c7/0x2d0 fs/aio.c:2174
Read of size 4 at addr ffff88801f857020 by task syz-executor142/5065

CPU: 0 PID: 5065 Comm: syz-executor142 Not tainted 6.8.0-rc6-syzkaller-00238-g5ad3cb0ed525 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x167/0x540 mm/kasan/report.c:488
kasan_report+0x142/0x180 mm/kasan/report.c:601
__do_sys_io_cancel fs/aio.c:2207 [inline]
__se_sys_io_cancel+0x2c7/0x2d0 fs/aio.c:2174
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f1c0c3bd3e9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe5ffcdc98 EFLAGS: 00000246 ORIG_RAX: 00000000000000d2
RAX: ffffffffffffffda RBX: 00007ffe5ffcde68 RCX: 00007f1c0c3bd3e9
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 00007f1c0c349000
RBP: 00007f1c0c430610 R08: 00007ffe5ffcde68 R09: 00007ffe5ffcde68
R10: 00007ffe5ffcde68 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe5ffcde58 R14: 0000000000000001 R15: 0000000000000001
</TASK>

Allocated by task 5065:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:312 [inline]
__kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
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]
kmem_cache_alloc+0x16f/0x340 mm/slub.c:3867
aio_get_req fs/aio.c:1060 [inline]
io_submit_one+0x154/0x18b0 fs/aio.c:2050
__do_sys_io_submit fs/aio.c:2113 [inline]
__se_sys_io_submit+0x17f/0x300 fs/aio.c:2083
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77

Freed by task 4812:
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:589
poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
__kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kmem_cache_free+0x102/0x2a0 mm/slub.c:4363
aio_poll_complete_work+0x467/0x670 fs/aio.c:1767
process_one_work kernel/workqueue.c:2633 [inline]
process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706
worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
kthread+0x2ef/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243

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:551
insert_work+0x3e/0x330 kernel/workqueue.c:1653
__queue_work+0xbf4/0x1000 kernel/workqueue.c:1802
queue_work_on+0x14f/0x250 kernel/workqueue.c:1837
queue_work include/linux/workqueue.h:548 [inline]
schedule_work include/linux/workqueue.h:609 [inline]
aio_poll_cancel+0xbb/0x130 fs/aio.c:1779
__do_sys_io_cancel fs/aio.c:2196 [inline]
__se_sys_io_cancel+0x126/0x2d0 fs/aio.c:2174
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77

The buggy address belongs to the object at ffff88801f857000
which belongs to the cache aio_kiocb of size 216
The buggy address is located 32 bytes inside of
freed 216-byte region [ffff88801f857000, ffff88801f8570d8)

The buggy address belongs to the physical page:
page:ffffea00007e15c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1f857
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff88801a6a9500 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 5065, tgid 5065 (syz-executor142), ts 69523425470, free_ts 63195641417
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
__alloc_pages+0x255/0x680 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+0x5f/0x160 mm/slub.c:2190
allocate_slab mm/slub.c:2354 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2407
___slab_alloc+0xd17/0x13e0 mm/slub.c:3540
__slab_alloc mm/slub.c:3625 [inline]
__slab_alloc_node mm/slub.c:3678 [inline]
slab_alloc_node mm/slub.c:3850 [inline]
kmem_cache_alloc+0x24d/0x340 mm/slub.c:3867
aio_get_req fs/aio.c:1060 [inline]
io_submit_one+0x154/0x18b0 fs/aio.c:2050
__do_sys_io_submit fs/aio.c:2113 [inline]
__se_sys_io_submit+0x17f/0x300 fs/aio.c:2083
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77
page last free pid 4504 tgid 4504 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+0x968/0xa90 mm/page_alloc.c:2346
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
__slab_free+0x349/0x410 mm/slub.c:4211
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x5e/0xc0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
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]
kmem_cache_alloc+0x16f/0x340 mm/slub.c:3867
getname_flags+0xbc/0x4f0 fs/namei.c:140
do_sys_openat2+0xd2/0x1d0 fs/open.c:1398
do_sys_open fs/open.c:1419 [inline]
__do_sys_openat fs/open.c:1435 [inline]
__se_sys_openat fs/open.c:1430 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1430
do_syscall_64+0xf9/0x240
entry_SYSCALL_64_after_hwframe+0x6f/0x77

Memory state around the buggy address:
ffff88801f856f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801f856f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88801f857000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801f857080: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
ffff88801f857100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

---
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Next message: Duoming Zhou: "[PATCH] nouveau/dmem: handle kcalloc() allocation failure"
Previous message: Greg Kroah-Hartman: "Re: CVE-2023-52466: PCI: Avoid potential out-of-bounds read in pci_dev_for_each_resource()"
Next in thread: Edward Adam Davis: "Re: [syzbot] [fs?] KASAN: slab-use-after-free Read in sys_io_cancel"
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