syzbot


KASAN: use-after-free Read in io_wqe_worker

Status: fixed on 2020/11/16 12:12
Subsystems: fs io-uring
[Documentation on labels]
Reported-by: syzbot+9af99580130003da82b1@syzkaller.appspotmail.com
Fix commit: c4068bf898dd io-wq: fix use-after-free in io_wq_worker_running
First crash: 1334d, last: 1329d
Cause bisection: failed (error log, bisect log)
  
Discussions (4)
Title Replies (including bot) Last reply
[PATCH 5.9 00/74] 5.9.3-rc1 review 85 (85) 2020/11/03 07:54
[PATCH 5.8 00/70] 5.8.18-rc1 review 73 (73) 2020/11/01 07:19
Re: [PATCH next] io-wq: fix use-after-free in io_wq_worker_running 2 (2) 2020/09/26 18:35
KASAN: use-after-free Read in io_wqe_worker 3 (6) 2020/09/26 14:15
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in io_wqe_worker (2) io-uring C error done 3 464d 495d 0/26 auto-obsoleted due to no activity on 2023/06/09 07:06
Last patch testing requests (2)
Created Duration User Patch Repo Result
2020/09/26 12:57 17m axboe@kernel.dk git://git.kernel.dk/linux-block.git 41d5f92f60a61e264dafbada79175dad0bc60c5b OK
2020/09/26 12:22 16m axboe@kernel.dk git://git.kernel.dk/linux-block io_uring-5.9 OK

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x92/0x2ae0 kernel/locking/lockdep.c:4311
Read of size 8 at addr ffff88821ae5f818 by task io_wqe_worker-0/11054

CPU: 1 PID: 11054 Comm: io_wqe_worker-0 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d6/0x29e lib/dump_stack.c:118
 print_address_description+0x66/0x620 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 __lock_acquire+0x92/0x2ae0 kernel/locking/lockdep.c:4311
 lock_acquire+0x148/0x720 kernel/locking/lockdep.c:5029
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
 _raw_spin_lock_irq+0xa6/0xc0 kernel/locking/spinlock.c:167
 spin_lock_irq include/linux/spinlock.h:379 [inline]
 io_wqe_worker+0x756/0x810 fs/io-wq.c:589
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Allocated by task 11048:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
 kmem_cache_alloc_node_trace+0x1f7/0x2a0 mm/slab.c:3594
 kmalloc_node include/linux/slab.h:572 [inline]
 kzalloc_node include/linux/slab.h:677 [inline]
 io_wq_create+0x295/0x880 fs/io-wq.c:1064
 io_init_wq_offload fs/io_uring.c:7432 [inline]
 io_sq_offload_start fs/io_uring.c:7504 [inline]
 io_uring_create fs/io_uring.c:8625 [inline]
 io_uring_setup fs/io_uring.c:8694 [inline]
 __do_sys_io_uring_setup fs/io_uring.c:8700 [inline]
 __se_sys_io_uring_setup+0x18ed/0x2a00 fs/io_uring.c:8697
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 128:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kfree+0x113/0x200 mm/slab.c:3756
 __io_wq_destroy fs/io-wq.c:1138 [inline]
 io_wq_destroy+0x470/0x510 fs/io-wq.c:1146
 io_finish_async fs/io_uring.c:6836 [inline]
 io_ring_ctx_free fs/io_uring.c:7870 [inline]
 io_ring_exit_work+0x195/0x520 fs/io_uring.c:7954
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff88821ae5f800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 24 bytes inside of
 1024-byte region [ffff88821ae5f800, ffff88821ae5fc00)
The buggy address belongs to the page:
page:000000008e41b1c2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21ae5f
flags: 0x57ffe0000000200(slab)
raw: 057ffe0000000200 ffffea00086a10c8 ffffea00085d1848 ffff8880aa440700
raw: 0000000000000000 ffff88821ae5f000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88821ae5f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88821ae5f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88821ae5f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88821ae5f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88821ae5f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/09/22 10:51 upstream 98477740630f 9e1fa68e .config console log report syz C ci-upstream-kasan-gce-smack-root
2020/09/27 23:42 upstream a1bffa48745a 5dd8aee8 .config console log report info ci-upstream-kasan-gce-selinux-root
* Struck through repros no longer work on HEAD.