[syzbot] [kernel?] KASAN: slab-use-after-free Write in expire_timers

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syzbot

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May 3, 2023, 4:17:55 PM5/3/23
to ak...@linux-foundation.org, linux-...@vger.kernel.org, linu...@kvack.org, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 348551ddaf31 Merge tag 'pinctrl-v6.4-1' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=127eb988280000
kernel config: https://syzkaller.appspot.com/x/.config?x=35e09b26aabb80e5
dashboard link: https://syzkaller.appspot.com/bug?extid=7403ea5e821ac5a30b92
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7403ea...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:901 [inline]
BUG: KASAN: slab-use-after-free in detach_timer kernel/time/timer.c:880 [inline]
BUG: KASAN: slab-use-after-free in expire_timers+0x476/0x4b0 kernel/time/timer.c:1734
Write of size 8 at addr ffff888028d29500 by task syz-executor.3/13686

CPU: 2 PID: 13686 Comm: syz-executor.3 Not tainted 6.3.0-syzkaller-12728-g348551ddaf31 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
__hlist_del include/linux/list.h:901 [inline]
detach_timer kernel/time/timer.c:880 [inline]
expire_timers+0x476/0x4b0 kernel/time/timer.c:1734
__run_timers kernel/time/timer.c:2022 [inline]
__run_timers kernel/time/timer.c:1995 [inline]
run_timer_softirq+0x326/0x910 kernel/time/timer.c:2035
__do_softirq+0x1d4/0x905 kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x114/0x190 kernel/softirq.c:650
irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1106
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:lock_acquire+0x1f5/0x520 kernel/locking/lockdep.c:5659
Code: 65 9d 7e 83 f8 01 0f 85 b9 02 00 00 9c 58 f6 c4 02 0f 85 a4 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24
RSP: 0000:ffffc90003cbf220 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff92000797e46 RCX: ffffffff8164ca56
RDX: 1ffff11004149c18 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff9151dd17
R10: fffffbfff22a3ba2 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8c90a3e0 R15: 0000000000000000
fs_reclaim_acquire mm/page_alloc.c:3901 [inline]
fs_reclaim_acquire+0xda/0x160 mm/page_alloc.c:3892
might_alloc include/linux/sched/mm.h:303 [inline]
prepare_alloc_pages+0x159/0x570 mm/page_alloc.c:4530
__alloc_pages+0x149/0x4a0 mm/page_alloc.c:4748
alloc_pages+0x1aa/0x270 mm/mempolicy.c:2277
folio_alloc+0x20/0x70 mm/mempolicy.c:2287
filemap_alloc_folio+0x3c1/0x470 mm/filemap.c:976
__filemap_get_folio+0x2a6/0x990 mm/filemap.c:1965
pagecache_get_page+0x2e/0x270 mm/folio-compat.c:99
find_or_create_page include/linux/pagemap.h:635 [inline]
grow_dev_page fs/buffer.c:995 [inline]
grow_buffers fs/buffer.c:1060 [inline]
__getblk_slow+0x1f2/0x1230 fs/buffer.c:1087
__getblk_gfp+0x72/0x80 fs/buffer.c:1382
__getblk include/linux/buffer_head.h:420 [inline]
reiserfs_breada+0x15f/0x470 fs/reiserfs/journal.c:2338
journal_read fs/reiserfs/journal.c:2449 [inline]
journal_init+0x23dd/0x64b0 fs/reiserfs/journal.c:2897
reiserfs_fill_super+0xc5b/0x2eb0 fs/reiserfs/super.c:2022
mount_bdev+0x357/0x420 fs/super.c:1380
legacy_get_tree+0x109/0x220 fs/fs_context.c:610
vfs_get_tree+0x8d/0x350 fs/super.c:1510
do_new_mount fs/namespace.c:3039 [inline]
path_mount+0x134b/0x1e40 fs/namespace.c:3369
do_mount fs/namespace.c:3382 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x283/0x300 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc3ca28d69a
Code: 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 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:00007fc3c8dfdf88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 000000000000ffb6 RCX: 00007fc3ca28d69a
RDX: 000000002000ffc0 RSI: 0000000020010000 RDI: 00007fc3c8dfdfe0
RBP: 00007fc3c8dfe020 R08: 00007fc3c8dfe020 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000002000ffc0
R13: 0000000020010000 R14: 00007fc3c8dfdfe0 R15: 0000000020010040
</TASK>

Allocated by task 11731:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
__kasan_slab_alloc+0x7f/0x90 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:186 [inline]
slab_post_alloc_hook mm/slab.h:711 [inline]
slab_alloc_node mm/slab.c:3256 [inline]
slab_alloc mm/slab.c:3265 [inline]
__kmem_cache_alloc_lru mm/slab.c:3442 [inline]
kmem_cache_alloc+0x1bd/0x3f0 mm/slab.c:3451
getname_flags.part.0+0x50/0x4f0 fs/namei.c:140
getname_flags include/linux/audit.h:321 [inline]
getname+0x92/0xd0 fs/namei.c:219
do_sys_openat2+0xf5/0x4c0 fs/open.c:1350
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x143/0x1f0 fs/open.c:1383
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 11731:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:521
____kasan_slab_free mm/kasan/common.c:236 [inline]
____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200
kasan_slab_free include/linux/kasan.h:162 [inline]
__cache_free mm/slab.c:3389 [inline]
__do_kmem_cache_free mm/slab.c:3576 [inline]
kmem_cache_free mm/slab.c:3601 [inline]
kmem_cache_free+0x105/0x370 mm/slab.c:3594
putname fs/namei.c:273 [inline]
putname+0x102/0x140 fs/namei.c:259
do_sys_openat2+0x153/0x4c0 fs/open.c:1365
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x143/0x1f0 fs/open.c:1383
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888028d28b40
which belongs to the cache names_cache of size 4096
The buggy address is located 2496 bytes inside of
freed 4096-byte region [ffff888028d28b40, ffff888028d29b40)

The buggy address belongs to the physical page:
page:ffffea0000a34a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28d28
head:ffffea0000a34a00 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0x1()
raw: 00fff00000010200 ffff888040059f00 ffffea0000a7a590 ffffea0000a24d10
raw: 0000000000000000 ffff888028d28b40 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 11731, tgid 11731 (udevd), ts 458697775213, free_ts 458620276328
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1722
prep_new_page mm/page_alloc.c:1729 [inline]
get_page_from_freelist+0xf41/0x2c00 mm/page_alloc.c:3493
__alloc_pages_slowpath.constprop.0+0x2e7/0x2170 mm/page_alloc.c:4293
__alloc_pages+0x408/0x4a0 mm/page_alloc.c:4772
__alloc_pages_node include/linux/gfp.h:237 [inline]
kmem_getpages mm/slab.c:1360 [inline]
cache_grow_begin+0x9b/0x3b0 mm/slab.c:2569
cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
____cache_alloc mm/slab.c:3018 [inline]
____cache_alloc mm/slab.c:3001 [inline]
__do_cache_alloc mm/slab.c:3201 [inline]
slab_alloc_node mm/slab.c:3249 [inline]
slab_alloc mm/slab.c:3265 [inline]
__kmem_cache_alloc_lru mm/slab.c:3442 [inline]
kmem_cache_alloc+0x397/0x3f0 mm/slab.c:3451
getname_flags.part.0+0x50/0x4f0 fs/namei.c:140
getname_flags include/linux/audit.h:321 [inline]
getname+0x92/0xd0 fs/namei.c:219
do_sys_openat2+0xf5/0x4c0 fs/open.c:1350
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x143/0x1f0 fs/open.c:1383
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 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:1302 [inline]
free_unref_page_prepare+0x62e/0xcb0 mm/page_alloc.c:2555
free_unref_page+0x33/0x370 mm/page_alloc.c:2650
slab_destroy mm/slab.c:1612 [inline]
drain_freelist.isra.0+0xdd/0x130 mm/slab.c:2205
cache_reap+0x1bd/0x2e0 mm/slab.c:3870
process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
kthread+0x344/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Memory state around the buggy address:
ffff888028d29400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888028d29480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028d29500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888028d29580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888028d29600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 65 9d gs popfq
2: 7e 83 jle 0xffffff87
4: f8 clc
5: 01 0f add %ecx,(%rdi)
7: 85 b9 02 00 00 9c test %edi,-0x63fffffe(%rcx)
d: 58 pop %rax
e: f6 c4 02 test $0x2,%ah
11: 0f 85 a4 02 00 00 jne 0x2bb
17: 48 83 7c 24 08 00 cmpq $0x0,0x8(%rsp)
1d: 74 01 je 0x20
1f: fb sti
20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
27: fc ff df
* 2a: 48 01 c3 add %rax,%rbx <-- trapping instruction
2d: 48 c7 03 00 00 00 00 movq $0x0,(%rbx)
34: 48 c7 43 08 00 00 00 movq $0x0,0x8(%rbx)
3b: 00
3c: 48 rex.W
3d: 8b .byte 0x8b
3e: 84 .byte 0x84
3f: 24 .byte 0x24


---
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syzbot

unread,
Aug 23, 2023, 5:02:47 AM8/23/23
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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