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

From: syzbot
Date: Mon Nov 21 2022 - 13:35:45 EST

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Hello,

syzbot found the following issue on:

HEAD commit: b6e7fdfd6f6a Merge tag 'iommu-fixes-v6.1-rc5' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11c28f95880000
kernel config: https://syzkaller.appspot.com/x/.config?x=95fb379f123ba8ce
dashboard link: https://syzkaller.appspot.com/bug?extid=38ee3533e07da8749f85
compiler: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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+38ee3533e07da8749f85@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:885 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:880 [inline]
BUG: KASAN: use-after-free in expire_timers+0x74/0xc4 kernel/time/timer.c:1508
Write at addr f8ff000005c37858 by task syz-executor.1/2271
Pointer tag: [f8], memory tag: [fe]

CPU: 0 PID: 2271 Comm: syz-executor.1 Not tainted 6.1.0-rc5-syzkaller-00320-gb6e7fdfd6f6a #0
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace.part.0+0xe0/0xf0 arch/arm64/kernel/stacktrace.c:156
dump_backtrace arch/arm64/kernel/stacktrace.c:162 [inline]
show_stack+0x18/0x40 arch/arm64/kernel/stacktrace.c:163
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x68/0x84 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x1a8/0x4a0 mm/kasan/report.c:395
kasan_report+0x94/0xb4 mm/kasan/report.c:495
__do_kernel_fault+0x164/0x1e0 arch/arm64/mm/fault.c:320
do_bad_area arch/arm64/mm/fault.c:473 [inline]
do_tag_check_fault+0x78/0x8c arch/arm64/mm/fault.c:749
do_mem_abort+0x44/0x94 arch/arm64/mm/fault.c:825
el1_abort+0x40/0x60 arch/arm64/kernel/entry-common.c:367
el1h_64_sync_handler+0xd8/0xe4 arch/arm64/kernel/entry-common.c:427
el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:576
__hlist_del include/linux/list.h:885 [inline]
detach_timer kernel/time/timer.c:880 [inline]
expire_timers+0x74/0xc4 kernel/time/timer.c:1508
__run_timers kernel/time/timer.c:1790 [inline]
__run_timers kernel/time/timer.c:1763 [inline]
run_timer_softirq+0xf4/0x254 kernel/time/timer.c:1803
_stext+0x124/0x2a4
____do_softirq+0x10/0x20 arch/arm64/kernel/irq.c:79
call_on_irq_stack+0x2c/0x5c arch/arm64/kernel/entry.S:889
do_softirq_own_stack+0x1c/0x30 arch/arm64/kernel/irq.c:84
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xcc/0xf4 kernel/softirq.c:650
irq_exit_rcu+0x10/0x20 kernel/softirq.c:662
el0_interrupt+0x54/0x104 arch/arm64/kernel/entry-common.c:717
__el0_irq_handler_common+0x18/0x2c arch/arm64/kernel/entry-common.c:724
el0t_64_irq_handler+0x10/0x20 arch/arm64/kernel/entry-common.c:729
el0t_64_irq+0x198/0x19c arch/arm64/kernel/entry.S:582

Allocated by task 3867:
kasan_save_stack+0x2c/0x60 mm/kasan/common.c:45
save_stack_info+0x38/0x130 mm/kasan/tags.c:104
kasan_save_alloc_info+0x14/0x20 mm/kasan/tags.c:138
____kasan_kmalloc mm/kasan/common.c:371 [inline]
____kasan_kmalloc mm/kasan/common.c:330 [inline]
__kasan_kmalloc+0x9c/0xb0 mm/kasan/common.c:380
kasan_kmalloc include/linux/kasan.h:211 [inline]
kmalloc_trace+0x5c/0x70 mm/slab_common.c:1050
kmalloc include/linux/slab.h:553 [inline]
kzalloc include/linux/slab.h:689 [inline]
nci_allocate_device net/nfc/nci/core.c:1157 [inline]
nci_allocate_device+0x5c/0x170 net/nfc/nci/core.c:1143
virtual_ncidev_open+0x54/0xe0 drivers/nfc/virtual_ncidev.c:139
misc_open+0x124/0x170 drivers/char/misc.c:143
chrdev_open+0xc0/0x260 fs/char_dev.c:414
do_dentry_open+0x13c/0x4d0 fs/open.c:882
vfs_open+0x2c/0x40 fs/open.c:1013
do_open fs/namei.c:3557 [inline]
path_openat+0x568/0xee0 fs/namei.c:3713
do_filp_open+0x80/0x130 fs/namei.c:3740
do_sys_openat2+0xb4/0x16c fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_openat fs/open.c:1342 [inline]
__se_sys_openat fs/open.c:1337 [inline]
__arm64_sys_openat+0x64/0xb0 fs/open.c:1337
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52
el0_svc_common.constprop.0+0x44/0xec arch/arm64/kernel/syscall.c:142
do_el0_svc+0x2c/0xd0 arch/arm64/kernel/syscall.c:206
el0_svc+0x2c/0xb0 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581

Freed by task 3864:
kasan_save_stack+0x2c/0x60 mm/kasan/common.c:45
save_stack_info+0x38/0x130 mm/kasan/tags.c:104
kasan_save_free_info+0x18/0x30 mm/kasan/tags.c:143
____kasan_slab_free.constprop.0+0x1b8/0x230 mm/kasan/common.c:236
__kasan_slab_free+0x10/0x1c mm/kasan/common.c:244
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1724 [inline]
slab_free_freelist_hook+0xbc/0x1fc mm/slub.c:1750
slab_free mm/slub.c:3661 [inline]
__kmem_cache_free+0x16c/0x2ec mm/slub.c:3674
kfree+0x60/0xb0 mm/slab_common.c:1007
nci_free_device+0x30/0x40 net/nfc/nci/core.c:1205
virtual_ncidev_close+0x74/0x80 drivers/nfc/virtual_ncidev.c:167
__fput+0x78/0x260 fs/file_table.c:320
____fput+0x10/0x20 fs/file_table.c:348
task_work_run+0x80/0xe0 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
do_notify_resume+0x218/0x13b0 arch/arm64/kernel/signal.c:1127
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
el0_svc+0xac/0xb0 arch/arm64/kernel/entry-common.c:638
el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581

The buggy address belongs to the object at ffff000005c37800
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 88 bytes inside of
2048-byte region [ffff000005c37800, ffff000005c38000)

The buggy address belongs to the physical page:
page:000000007e5956af refcount:1 mapcount:0 mapping:0000000000000000 index:0xfcff000005c37800 pfn:0x45c30
head:000000007e5956af order:3 compound_mapcount:0 compound_pincount:0
flags: 0x1ffc00000010200(slab|head|node=0|zone=0|lastcpupid=0x7ff|kasantag=0x0)
raw: 01ffc00000010200 0000000000000000 dead000000000001 f6ff000002c01600
raw: fcff000005c37800 000000008010000d 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff000005c37600: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
ffff000005c37700: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>ffff000005c37800: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
^
ffff000005c37900: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
ffff000005c37a00: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
==================================================================
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x0000000086000005
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x05: level 1 translation fault
user pgtable: 4k pages, 48-bit VAs, pgdp=000000004526f000
[0000000000000000] pgd=0800000045ef2003, p4d=0800000045ef2003, pud=0000000000000000
Internal error: Oops: 0000000086000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 2271 Comm: syz-executor.1 Tainted: G B 6.1.0-rc5-syzkaller-00320-gb6e7fdfd6f6a #0
Hardware name: linux,dummy-virt (DT)
pstate: 60400809 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=-c)
pc : 0x0
lr : call_timer_fn.constprop.0+0x24/0x80 kernel/time/timer.c:1474
sp : ffff800008003e70
x29: ffff800008003e70 x28: 0000000000000007 x27: 0000000000000080
x26: fcff000002c5ee40 x25: ffff80000a2b60c0 x24: ffff80000a2b60c8
x23: dead000000000122 x22: 0000000000000000 x21: 0000000000000100
x20: fcff000002c5ee40 x19: 0000000000000000 x18: 0000000000000000
x17: ffff800075918000 x16: ffff800008004000 x15: 0000000000004000
x14: 00000000000000f7 x13: 0000000000000001 x12: ffff00007fbb7068
x11: 0000000000000001 x10: 408a800000000a00 x9 : 000000000000006e
x8 : 2000000000000000 x7 : 0000000000000001 x6 : ffff00007fbb7028
x5 : 0000000000000001 x4 : 0000000000000000 x3 : ffff800008003f20
x2 : 0000000000000000 x1 : 0000000000000000 x0 : f8ff000005c37850
Call trace:
0x0
expire_timers+0x98/0xc4 kernel/time/timer.c:1519
__run_timers kernel/time/timer.c:1790 [inline]
__run_timers kernel/time/timer.c:1763 [inline]
run_timer_softirq+0xf4/0x254 kernel/time/timer.c:1803
_stext+0x124/0x2a4
____do_softirq+0x10/0x20 arch/arm64/kernel/irq.c:79
call_on_irq_stack+0x2c/0x5c arch/arm64/kernel/entry.S:889
do_softirq_own_stack+0x1c/0x30 arch/arm64/kernel/irq.c:84
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xcc/0xf4 kernel/softirq.c:650
irq_exit_rcu+0x10/0x20 kernel/softirq.c:662
el0_interrupt+0x54/0x104 arch/arm64/kernel/entry-common.c:717
__el0_irq_handler_common+0x18/0x2c arch/arm64/kernel/entry-common.c:724
el0t_64_irq_handler+0x10/0x20 arch/arm64/kernel/entry-common.c:729
el0t_64_irq+0x198/0x19c arch/arm64/kernel/entry.S:582
Code: bad PC value
---[ end trace 0000000000000000 ]---

---
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Next message: Andy Shevchenko: "Re: [PATCH v2 2/2] iio: magnetometer: add ti tmag5273 driver"
Previous message: James Houghton: "Re: [RFC PATCH v2 01/47] hugetlb: don't set PageUptodate for UFFDIO_CONTINUE"
Next in thread: Yu Liao: "Re: [syzbot] KASAN: use-after-free Write in expire_timers"
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