KASAN: slab-out-of-bounds Write in __run_timers

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cd5f5cb9 ANDROID: GKI: Export memblock_free to drivers
git tree: android12-5.4
console output: https://syzkaller.appspot.com/x/log.txt?x=15714333500000
kernel config: https://syzkaller.appspot.com/x/.config?x=17c7bb5b502bc58a
dashboard link: https://syzkaller.appspot.com/bug?extid=b9125f9f83b03d388605
compiler: Android (6032204 based on r370808) clang version 10.0.1 (https://android.googlesource.com/toolchain/llvm-project 6e765c10313d15c02ab29977a82938f66742c3a9)

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+b9125f...@syzkaller.appspotmail.com

BUG: KASAN: slab-out-of-bounds in hlist_move_list include/linux/list.h:843 [inline]
BUG: KASAN: slab-out-of-bounds in __collect_expired_timers kernel/time/timer.c:1482 [inline]
BUG: KASAN: slab-out-of-bounds in collect_expired_timers kernel/time/timer.c:1717 [inline]
BUG: KASAN: slab-out-of-bounds in __run_timers+0x54e/0x7a0 kernel/time/timer.c:1781
Write of size 8 at addr ffff8881e20371c8 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.84-syzkaller-00151-gcd5f5cb9fe67 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1dd/0x24e lib/dump_stack.c:118
print_address_description+0x96/0x640 mm/kasan/report.c:374
__kasan_report+0x177/0x1f0 mm/kasan/report.c:506
kasan_report+0x30/0x60 mm/kasan/common.c:634
hlist_move_list include/linux/list.h:843 [inline]
__collect_expired_timers kernel/time/timer.c:1482 [inline]
collect_expired_timers kernel/time/timer.c:1717 [inline]
__run_timers+0x54e/0x7a0 kernel/time/timer.c:1781
run_timer_softirq+0x46/0x80 kernel/time/timer.c:1798
__do_softirq+0x30f/0x769 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x1b4/0x1c0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:546 [inline]
smp_apic_timer_interrupt+0x2d1/0x460 arch/x86/kernel/apic/apic.c:1146
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:831
</IRQ>
RIP: 0010:default_idle+0x1f/0x30 arch/x86/kernel/process.c:573
Code: fe ff ff e8 73 2b fb fc 90 90 90 e8 fb 33 e8 fd bf 01 00 00 00 89 c6 e8 3f 02 e8 fc e9 07 00 00 00 0f 00 2d 8b cc 60 00 fb f4 <e8> dc 33 e8 fd bf ff ff ff ff 89 c6 e9 20 02 e8 fc 41 57 41 56 53
RSP: 0018:ffffffff85407d18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff85414940 RCX: ffffffff85414940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffffff85407e20 R08: ffffffff82297b30 R09: fffffbfff0a82929
R10: fffffbfff0a82929 R11: 0000000000000000 R12: ffffffff855c7260
R13: 1ffffffff0a82928 R14: dffffc0000000000 R15: 0000000000000000
default_idle_call kernel/sched/idle.c:94 [inline]
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x218/0x5f0 kernel/sched/idle.c:263
cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:355
start_kernel+0x701/0x848 init/main.c:1044
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241

Allocated by task 146:
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x129/0x1c0 mm/kasan/common.c:510
kmem_cache_alloc_trace+0xc3/0x290 mm/slub.c:2830
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:690 [inline]
kernfs_iop_get_link+0x63/0x550 fs/kernfs/symlink.c:135
vfs_readlink+0x185/0x420 fs/namei.c:4815
do_readlinkat+0x29f/0x3c0 fs/stat.c:411
__do_sys_readlinkat fs/stat.c:426 [inline]
__se_sys_readlinkat fs/stat.c:423 [inline]
__x64_sys_readlinkat+0x96/0xb0 fs/stat.c:423
do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 146:
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x17e/0x230 mm/kasan/common.c:471
slab_free_hook mm/slub.c:1453 [inline]
slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1486
slab_free mm/slub.c:3051 [inline]
kfree+0x12c/0x660 mm/slub.c:4017
do_delayed_call include/linux/delayed_call.h:28 [inline]
vfs_readlink+0x261/0x420 fs/namei.c:4820
do_readlinkat+0x29f/0x3c0 fs/stat.c:411
__do_sys_readlinkat fs/stat.c:426 [inline]
__se_sys_readlinkat fs/stat.c:423 [inline]
__x64_sys_readlinkat+0x96/0xb0 fs/stat.c:423
do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8881e2036000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 456 bytes to the right of
4096-byte region [ffff8881e2036000, ffff8881e2037000)
The buggy address belongs to the page:
page:ffffea0007880c00 refcount:1 mapcount:0 mapping:ffff8881f600c280 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f600c280
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881e2037080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881e2037100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881e2037180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881e2037200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881e2037280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.