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Message-ID: <000000000000ce9d000616315c11@google.com>
Date: Tue, 16 Apr 2024 00:05:26 -0700
From: syzbot <syzbot+dce04ed6d1438ad69656@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, peterz@...radead.org,
syzkaller-bugs@...glegroups.com, tglx@...utronix.de
Subject: Re: [syzbot] [kernel?] WARNING: suspicious RCU usage in __do_softirq
syzbot has found a reproducer for the following issue on:
HEAD commit: 6bd343537461 Add linux-next specific files for 20240415
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=132b923b180000
kernel config: https://syzkaller.appspot.com/x/.config?x=c247afaa437e6409
dashboard link: https://syzkaller.appspot.com/bug?extid=dce04ed6d1438ad69656
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11e7ff77180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=125e7767180000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/aaf63ca280e5/disk-6bd34353.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/353fdc5b9ee6/vmlinux-6bd34353.xz
kernel image: https://storage.googleapis.com/syzbot-assets/25a7a362b023/bzImage-6bd34353.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dce04ed6d1438ad69656@...kaller.appspotmail.com
=============================
WARNING: suspicious RCU usage
6.9.0-rc4-next-20240415-syzkaller #0 Not tainted
-----------------------------
kernel/rcu/tree.c:276 Illegal rcu_softirq_qs() in RCU read-side critical section!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by ksoftirqd/0/16:
#0: ffffffff8e334160
(rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
(rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:933 [inline]
(rcu_read_lock_sched){....}-{1:2}, at: pfn_valid include/linux/mmzone.h:2019 [inline]
(rcu_read_lock_sched){....}-{1:2}, at: __virt_addr_valid+0x183/0x520 arch/x86/mm/physaddr.c:65
stack backtrace:
CPU: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.9.0-rc4-next-20240415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
rcu_softirq_qs+0xd9/0x370 kernel/rcu/tree.c:273
__do_softirq+0x5fd/0x980 kernel/softirq.c:568
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5758
Code: 2b 00 74 08 4c 89 f7 e8 8a fd 88 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90000157820 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff9200002af10 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f8ee0
RBP: ffffc90000157980 R08: ffffffff92f765a7 R09: 1ffffffff25eecb4
R10: dffffc0000000000 R11: fffffbfff25eecb5 R12: 1ffff9200002af0c
R13: dffffc0000000000 R14: ffffc90000157880 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
rcu_read_lock_sched include/linux/rcupdate.h:933 [inline]
pfn_valid include/linux/mmzone.h:2019 [inline]
__virt_addr_valid+0x1a0/0x520 arch/x86/mm/physaddr.c:65
kasan_addr_to_slab+0xd/0x80 mm/kasan/common.c:37
__kasan_record_aux_stack+0x11/0xc0 mm/kasan/generic.c:526
__call_rcu_common kernel/rcu/tree.c:3102 [inline]
call_rcu+0x167/0xa70 kernel/rcu/tree.c:3206
context_switch kernel/sched/core.c:5412 [inline]
__schedule+0x17f0/0x4a50 kernel/sched/core.c:6746
preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6925
preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6949
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
smpboot_thread_fn+0x65b/0xa30 kernel/smpboot.c:163
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
----------------
Code disassembly (best guess):
0: 2b 00 sub (%rax),%eax
2: 74 08 je 0xc
4: 4c 89 f7 mov %r14,%rdi
7: e8 8a fd 88 00 call 0x88fd96
c: f6 44 24 61 02 testb $0x2,0x61(%rsp)
11: 0f 85 85 01 00 00 jne 0x19c
17: 41 f7 c7 00 02 00 00 test $0x200,%r15d
1e: 74 01 je 0x21
20: fb sti
21: 48 c7 44 24 40 0e 36 movq $0x45e0360e,0x40(%rsp)
28: e0 45
* 2a: 4b c7 44 25 00 00 00 movq $0x0,0x0(%r13,%r12,1) <-- trapping instruction
31: 00 00
33: 43 c7 44 25 09 00 00 movl $0x0,0x9(%r13,%r12,1)
3a: 00 00
3c: 43 rex.XB
3d: c7 .byte 0xc7
3e: 44 rex.R
3f: 25 .byte 0x25
---
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.
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