[syzbot] [kernel?] WARNING: locking bug in get_random_u8

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 929beafbe7ac Add linux-next specific files for 20241108
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14cb0ce8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=75175323f2078363
dashboard link: https://syzkaller.appspot.com/bug?extid=7f4f9a43a9c78eaee04f
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9705ecb6a595/disk-929beafb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dbdd1f64b9b8/vmlinux-929beafb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3f70d07a929b/bzImage-929beafb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7f4f9a...@syzkaller.appspotmail.com

=============================
[ BUG: Invalid wait context ]
6.12.0-rc6-next-20241108-syzkaller #0 Not tainted
-----------------------------
syz.4.319/7686 is trying to lock:
ffff8880b873a970 (batched_entropy_u8.lock){..-.}-{3:3}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
ffff8880b873a970 (batched_entropy_u8.lock){..-.}-{3:3}, at: get_random_u8+0x1a0/0xaa0 drivers/char/random.c:551
other info that might help us debug this:
context-{2:2}
no locks held by syz.4.319/7686.
stack backtrace:
CPU: 1 UID: 0 PID: 7686 Comm: syz.4.319 Not tainted 6.12.0-rc6-next-20241108-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline]
check_wait_context kernel/locking/lockdep.c:4898 [inline]
__lock_acquire+0x15a8/0x2100 kernel/locking/lockdep.c:5176
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
get_random_u8+0x1bd/0xaa0 drivers/char/random.c:551
get_random_u32_below include/linux/random.h:78 [inline]
kfence_guarded_alloc+0x9c/0xcd0 mm/kfence/core.c:421
__kfence_alloc+0x344/0x370 mm/kfence/core.c:1136
kfence_alloc include/linux/kfence.h:129 [inline]
slab_alloc_node mm/slub.c:4137 [inline]
__kmalloc_cache_noprof+0x2dd/0x390 mm/slub.c:4309
kmalloc_noprof include/linux/slab.h:901 [inline]
add_stack_record_to_list mm/page_owner.c:172 [inline]
inc_stack_record_count mm/page_owner.c:214 [inline]
__set_page_owner+0x55f/0x800 mm/page_owner.c:329
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0x3725/0x3870 mm/page_alloc.c:3510
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4786
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
stack_depot_save_flags+0x666/0x830 lib/stackdepot.c:627
kasan_save_stack+0x4f/0x60 mm/kasan/common.c:48
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
task_work_add+0xd9/0x490 kernel/task_work.c:77
__run_posix_cpu_timers kernel/time/posix-cpu-timers.c:1223 [inline]
run_posix_cpu_timers+0x6ac/0x810 kernel/time/posix-cpu-timers.c:1422
tick_sched_handle kernel/time/tick-sched.c:276 [inline]
tick_nohz_handler+0x37c/0x500 kernel/time/tick-sched.c:297
__run_hrtimer kernel/time/hrtimer.c:1739 [inline]
__hrtimer_run_queues+0x551/0xd50 kernel/time/hrtimer.c:1803
hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1865
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
__sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 ee 14 43 f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 43 99 a6 f5 65 8b 05 64 f3 3c 74 85 c0 74 43 48 c7 04 24 0e 36
RSP: 0018:ffffc900032efc60 EFLAGS: 00000206
RAX: 92c7e75658265800 RBX: 1ffff9200065df90 RCX: ffffffff9a3bf903
RDX: dffffc0000000000 RSI: ffffffff8c0ad880 RDI: 0000000000000001
RBP: ffffc900032efcf0 R08: ffffffff901c8877 R09: 1ffffffff203910e
R10: dffffc0000000000 R11: fffffbfff203910f R12: dffffc0000000000
R13: 1ffff9200065df8c R14: ffffc900032efc80 R15: 0000000000000246
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
unlock_timer kernel/time/posix-timers.c:128 [inline]
do_timer_settime+0x37f/0x3e0 kernel/time/posix-timers.c:908
__do_sys_timer_settime kernel/time/posix-timers.c:928 [inline]
__se_sys_timer_settime kernel/time/posix-timers.c:914 [inline]
__x64_sys_timer_settime+0x19e/0x240 kernel/time/posix-timers.c:914
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa02eb7e719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa02cff6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000df
RAX: ffffffffffffffda RBX: 00007fa02ed35f80 RCX: 00007fa02eb7e719
RDX: 0000000020000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00007fa02ebf1616 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa02ed35f80 R15: 00007ffd59aaea38
</TASK>
----------------
Code disassembly (best guess):
0: 9c pushf
1: 8f 44 24 20 pop 0x20(%rsp)
5: 42 80 3c 23 00 cmpb $0x0,(%rbx,%r12,1)
a: 74 08 je 0x14
c: 4c 89 f7 mov %r14,%rdi
f: e8 ee 14 43 f6 call 0xf6431502
14: f6 44 24 21 02 testb $0x2,0x21(%rsp)
19: 75 52 jne 0x6d
1b: 41 f7 c7 00 02 00 00 test $0x200,%r15d
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 43 99 a6 f5 call 0xf5a69972 <-- trapping instruction
2f: 65 8b 05 64 f3 3c 74 mov %gs:0x743cf364(%rip),%eax # 0x743cf39a
36: 85 c0 test %eax,%eax
38: 74 43 je 0x7d
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss


---
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[Hillf Danton]

Loop in lock people.

On Sat, 16 Nov 2024 08:09:30 -0800

Another locking issue in irq context [1].

[1] https://lore.kernel.org/all/20241102001224...@sina.com/

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 9f16d5e6f220 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16ee775f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d8bc8a5565eebec6
dashboard link: https://syzkaller.appspot.com/bug?extid=7f4f9a43a9c78eaee04f
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1612dee8580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-9f16d5e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dbaabe559df8/vmlinux-9f16d5e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5fe0afceb260/bzImage-9f16d5e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7f4f9a...@syzkaller.appspotmail.com

=============================
[ BUG: Invalid wait context ]

6.12.0-syzkaller-09073-g9f16d5e6f220 #0 Not tainted
-----------------------------
sshd/5973 is trying to lock:
ffff88806a63af60 (batched_entropy_u8.lock){..-.}-{3:3}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
ffff88806a63af60 (batched_entropy_u8.lock){..-.}-{3:3}, at: get_random_u8+0xef/0x7f0 drivers/char/random.c:551

other info that might help us debug this:
context-{2:2}

2 locks held by sshd/5973:
#0: ffffffff8e1bba80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8e1bba80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8e1bba80 (rcu_read_lock){....}-{1:3}, at: lock_vma_under_rcu+0xe4/0x980 mm/memory.c:6272
#1: ffff88806a63ebd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:598
stack backtrace:
CPU: 0 UID: 0 PID: 5973 Comm: sshd Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014

Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]

dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120

print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline]
check_wait_context kernel/locking/lockdep.c:4898 [inline]

__lock_acquire+0x878/0x3c40 kernel/locking/lockdep.c:5176
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
get_random_u8+0x107/0x7f0 drivers/char/random.c:551
get_random_u32_below include/linux/random.h:78 [inline]
kfence_guarded_alloc mm/kfence/core.c:421 [inline]
__kfence_alloc+0x4e8/0x15f0 mm/kfence/core.c:1136
kfence_alloc include/linux/kfence.h:129 [inline]
slab_alloc_node mm/slub.c:4118 [inline]
__kmalloc_cache_noprof+0x1e4/0x300 mm/slub.c:4290
kmalloc_noprof include/linux/slab.h:879 [inline]

add_stack_record_to_list mm/page_owner.c:172 [inline]
inc_stack_record_count mm/page_owner.c:214 [inline]

__set_page_owner+0x34d/0x560 mm/page_owner.c:329
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474
__alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4751
alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
stack_depot_save_flags+0x566/0x8f0 lib/stackdepot.c:627
kasan_save_stack+0x42/0x60 mm/kasan/common.c:48
__kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541
task_work_add+0xc0/0x3b0 kernel/task_work.c:77
task_tick_numa kernel/sched/fair.c:3607 [inline]
task_tick_fair+0x524/0x8e0 kernel/sched/fair.c:13054
sched_tick+0x1dd/0x4f0 kernel/sched/core.c:5652
update_process_times+0x19c/0x2d0 kernel/time/timer.c:2524
tick_sched_handle kernel/time/tick-sched.c:276 [inline]
tick_nohz_handler+0x376/0x530 kernel/time/tick-sched.c:297
__run_hrtimer kernel/time/hrtimer.c:1739 [inline]
__hrtimer_run_queues+0x5fb/0xae0 kernel/time/hrtimer.c:1803
hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1865
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
__sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049

</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

RIP: 0010:check_preemption_disabled+0x2/0xe0 lib/smp_processor_id.c:13
Code: 0f 65 8b 05 5c b2 d3 74 85 c0 74 04 90 0f 0b 90 e9 53 fc ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 54 <55> 53 48 83 ec 08 65 8b 1d ad 02 d5 74 65 8b 05 a2 02 d5 74 a9 ff
RSP: 0000:ffffc90003e1fc58 EFLAGS: 00000282
RAX: 0000000000000001 RBX: ffff88803221720c RCX: ffffffff8b1a7dad
RDX: 0000000000000001 RSI: ffffffff8bd1e0c0 RDI: ffffffff8bd1e100
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000006
R13: 0000000000000000 R14: 0000000000000300 R15: 00007f9bd4999fff
rcu_lockdep_current_cpu_online+0x35/0x150 kernel/rcu/tree.c:4777
rcu_read_lock_held_common kernel/rcu/update.c:113 [inline]
rcu_read_lock_held+0x27/0x50 kernel/rcu/update.c:349
mt_slot lib/maple_tree.c:803 [inline]
mtree_range_walk+0x25b/0xbe0 lib/maple_tree.c:2802
mas_state_walk lib/maple_tree.c:3620 [inline]
mas_walk+0x4f9/0x910 lib/maple_tree.c:4946
lock_vma_under_rcu+0x2b5/0x980 mm/memory.c:6274
do_user_addr_fault+0x457/0x13f0 arch/x86/mm/fault.c:1329
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x55f75beb0823
Code: 4c 89 ed 4c 89 e7 f3 aa eb 48 4c 89 e7 e8 95 48 f7 ff 48 89 c5 48 85 c0 74 38 48 89 c7 4c 89 ee 4d 39 f4 76 11 4c 89 f1 31 c0 <f3> a4 4c 89 e1 4c 29 f1 f3 aa eb 05 4c 89 e1 f3 a4 4c 89 ef 48 83
RSP: 002b:00007ffed36adfb0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000360000 RCX: 0000000000228010
RDX: 0000000000000002 RSI: 00007f9bd3f8c000 RDI: 00007f9bd461e000
RBP: 00007f9bd44ee010 R08: 00007f9bd44ee010 R09: 0000000000000000
R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000360000
R13: 00007f9bd3e5c010 R14: 0000000000358000 R15: 00007ffed36ae168
</TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 65 8b 05 5c b2 d3 74 mov %gs:0x74d3b25c(%rip),%eax # 0x74d3b263
7: 85 c0 test %eax,%eax
9: 74 04 je 0xf
b: 90 nop
c: 0f 0b ud2
e: 90 nop
f: e9 53 fc ff ff jmp 0xfffffc67
14: 0f 1f 00 nopl (%rax)
17: 90 nop
18: 90 nop
19: 90 nop
1a: 90 nop
1b: 90 nop
1c: 90 nop
1d: 90 nop
1e: 90 nop
1f: 90 nop
20: 90 nop
21: 90 nop
22: 90 nop
23: 90 nop
24: 90 nop
25: 90 nop
26: 90 nop
27: 41 54 push %r12
* 29: 55 push %rbp <-- trapping instruction
2a: 53 push %rbx
2b: 48 83 ec 08 sub $0x8,%rsp
2f: 65 8b 1d ad 02 d5 74 mov %gs:0x74d502ad(%rip),%ebx # 0x74d502e3
36: 65 8b 05 a2 02 d5 74 mov %gs:0x74d502a2(%rip),%eax # 0x74d502df
3d: a9 .byte 0xa9
3e: ff .byte 0xff


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[Sebastian Andrzej Siewior]

On 2024-11-25 04:41:23 [-0800], syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: 9f16d5e6f220 Merge tag 'for-linus' of git://git.kernel.org..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16ee775f980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d8bc8a5565eebec6
> dashboard link: https://syzkaller.appspot.com/bug?extid=7f4f9a43a9c78eaee04f
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1612dee8580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-9f16d5e6.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/dbaabe559df8/vmlinux-9f16d5e6.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/5fe0afceb260/bzImage-9f16d5e6.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+7f4f9a...@syzkaller.appspotmail.com

#syz fix: kasan: Make kasan_record_aux_stack_noalloc() the default behaviour
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bigeasy/staging.git 5cb0bc2a8ec81da5d1af5de29a6549c66c9254ad

Sebastian

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+7f4f9a...@syzkaller.appspotmail.com
Tested-by: syzbot+7f4f9a...@syzkaller.appspotmail.com

Tested on:

commit: 5cb0bc2a kasan: Make kasan_record_aux_stack_noalloc() ..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/bigeasy/staging.git
console output: https://syzkaller.appspot.com/x/log.txt?x=15f9f5c0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8839d3e536c93ebf

dashboard link: https://syzkaller.appspot.com/bug?extid=7f4f9a43a9c78eaee04f
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

[syzbot]

This bug is marked as fixed by commit:

kasan: Make kasan_record_aux_stack_noalloc() the default behaviour

But I can't find it in the tested trees[1] for more than 90 days.
Is it a correct commit? Please update it by replying:

#syz fix: exact-commit-title

Until then the bug is still considered open and new crashes with
the same signature are ignored.

Kernel: Linux
Dashboard link: https://syzkaller.appspot.com/bug?extid=7f4f9a43a9c78eaee04f

---
[1] I expect the commit to be present in:

1. for-kernelci branch of
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git

2. master branch of
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git

3. master branch of
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git

4. main branch of
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git

The full list of 10 trees can be found at
https://syzkaller.appspot.com/upstream/repos

[Sebastian Andrzej Siewior]

On 2025-02-24 06:51:16 [-0800], syzbot wrote:
> This bug is marked as fixed by commit:
> kasan: Make kasan_record_aux_stack_noalloc() the default behaviour
>
> But I can't find it in the tested trees[1] for more than 90 days.
> Is it a correct commit? Please update it by replying:
>

#syz fix: kasan: make kasan_record_aux_stack_noalloc() the default behaviour

Sebastian