From: syzbot <[email protected]>
To: [email protected], [email protected],
[email protected], [email protected],
[email protected]
Subject: Re: [syzbot] possible deadlock in io_sq_thread_finish
Date: Tue, 09 Mar 2021 20:12:04 -0800 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in io_sq_thread
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3e6f/0x54c0 kernel/locking/lockdep.c:4770
Read of size 8 at addr ffff88801d418c78 by task iou-sqp-10269/10271
CPU: 1 PID: 10271 Comm: iou-sqp-10269 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
__kasan_report mm/kasan/report.c:399 [inline]
kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
__lock_acquire+0x3e6f/0x54c0 kernel/locking/lockdep.c:4770
lock_acquire kernel/locking/lockdep.c:5510 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475
down_write+0x92/0x150 kernel/locking/rwsem.c:1406
io_sq_thread+0x1220/0x1b10 fs/io_uring.c:6754
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Allocated by task 10269:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:427 [inline]
____kasan_kmalloc mm/kasan/common.c:506 [inline]
____kasan_kmalloc mm/kasan/common.c:465 [inline]
__kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515
kmalloc include/linux/slab.h:554 [inline]
kzalloc include/linux/slab.h:684 [inline]
io_get_sq_data fs/io_uring.c:7153 [inline]
io_sq_offload_create fs/io_uring.c:7827 [inline]
io_uring_create fs/io_uring.c:9443 [inline]
io_uring_setup+0x154b/0x2940 fs/io_uring.c:9523
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 9:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
____kasan_slab_free mm/kasan/common.c:360 [inline]
____kasan_slab_free mm/kasan/common.c:325 [inline]
__kasan_slab_free+0xf5/0x130 mm/kasan/common.c:367
kasan_slab_free include/linux/kasan.h:199 [inline]
slab_free_hook mm/slub.c:1562 [inline]
slab_free_freelist_hook+0x92/0x210 mm/slub.c:1600
slab_free mm/slub.c:3161 [inline]
kfree+0xe5/0x7f0 mm/slub.c:4213
io_put_sq_data fs/io_uring.c:7095 [inline]
io_sq_thread_finish+0x48e/0x5b0 fs/io_uring.c:7113
io_ring_ctx_free fs/io_uring.c:8355 [inline]
io_ring_exit_work+0x333/0xcf0 fs/io_uring.c:8525
process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
kthread+0x3b1/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
The buggy address belongs to the object at ffff88801d418c00
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 120 bytes inside of
512-byte region [ffff88801d418c00, ffff88801d418e00)
The buggy address belongs to the page:
page:00000000311e6f59 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d418
head:00000000311e6f59 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff88800fc41c80
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88801d418b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88801d418b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801d418c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801d418c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88801d418d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: dc5c40fb io_uring: always wait for sqd exited when stoppin..
git tree: git://git.kernel.dk/linux-block io_uring-5.12
console output: https://syzkaller.appspot.com/x/log.txt?x=111d175cd00000
kernel config: https://syzkaller.appspot.com/x/.config?x=b3c6cab008c50864
dashboard link: https://syzkaller.appspot.com/bug?extid=ac39856cb1b332dbbdda
compiler:
next prev parent reply other threads:[~2021-03-10 4:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-07 9:49 [syzbot] possible deadlock in io_sq_thread_finish syzbot
2021-03-07 12:39 ` Pavel Begunkov
2021-03-07 13:20 ` Pavel Begunkov
2021-03-09 14:04 ` syzbot
2021-03-09 14:57 ` Jens Axboe
2021-03-09 22:29 ` syzbot
2021-03-09 23:34 ` Jens Axboe
2021-03-10 3:46 ` syzbot
2021-03-09 23:45 ` Jens Axboe
2021-03-10 4:12 ` syzbot [this message]
2021-03-10 14:37 ` Jens Axboe
2021-03-10 15:29 ` syzbot
[not found] ` <[email protected]>
2021-03-10 13:40 ` Pavel Begunkov
2021-03-10 14:26 ` Jens Axboe
2021-04-08 19:43 ` syzbot
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