syzbot


BUG: unable to handle kernel paging request in __run_timer_base

Status: upstream: reported syz repro on 2025/02/04 22:30
Subsystems: batman bcachefs
[Documentation on labels]
Reported-by: syzbot+ab2fd19057fa822e71c6@syzkaller.appspotmail.com
First crash: 4d08h, last: 4d08h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [batman?] [bcachefs?] BUG: unable to handle kernel paging request in __run_timer_base 0 (1) 2025/02/04 22:30

Sample crash report:
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle page fault for address: ffff8880465c3da0
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0011) - permissions violation
PGD 1aa01067 P4D 1aa01067 PUD 1aa04067 PMD 80000000464001e3 
Oops: Oops: 0011 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 3089 Comm: kworker/u4:10 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: bat_events batadv_nc_worker
RIP: 0010:0xffff8880465c3da0
Code: 00 00 00 00 00 00 00 00 00 00 01 03 06 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a8 3e 5c 46 80 88 ff ff <08> 3e 5c 46 80 88 ff ff b8 6f 54 59 80 88 ff ff 5b 15 00 00 f3 02
RSP: 0018:ffffc90000007b98 EFLAGS: 00010246
RAX: ffffffff81ac83d1 RBX: 0000000000000001 RCX: ffff88803b080000
RDX: 0000000000000100 RSI: ffffffff8c608040 RDI: ffff888059546f28
RBP: ffffc90000007c90 R08: ffffffff81ac83be R09: 1ffffffff203680e
R10: dffffc0000000000 R11: ffff8880465c3da0 R12: 1ffff92000000f78
R13: ffff888059546f28 R14: 0000000000000001 R15: 0000000000000100
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8880465c3da0 CR3: 0000000054b64000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 expire_timers kernel/time/timer.c:1840 [inline]
 __run_timers kernel/time/timer.c:2414 [inline]
 __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2426
 run_timer_base kernel/time/timer.c:2435 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2445
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 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:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5855
Code: 2b 00 74 08 4c 89 f7 e8 8a 2b 8b 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:ffffc9000db47940 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92001b68f34 RCX: ffff88803b080ae8
RDX: dffffc0000000000 RSI: ffffffff8c0ab8e0 RDI: ffffffff8c608060
RBP: ffffc9000db47aa0 R08: ffffffff942f6847 R09: 1ffffffff285ed08
R10: dffffc0000000000 R11: fffffbfff285ed09 R12: 1ffff92001b68f30
R13: dffffc0000000000 R14: ffffc9000db479a0 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xec/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
CR2: ffff8880465c3da0
---[ end trace 0000000000000000 ]---
RIP: 0010:0xffff8880465c3da0
Code: 00 00 00 00 00 00 00 00 00 00 01 03 06 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a8 3e 5c 46 80 88 ff ff <08> 3e 5c 46 80 88 ff ff b8 6f 54 59 80 88 ff ff 5b 15 00 00 f3 02
RSP: 0018:ffffc90000007b98 EFLAGS: 00010246
RAX: ffffffff81ac83d1 RBX: 0000000000000001 RCX: ffff88803b080000
RDX: 0000000000000100 RSI: ffffffff8c608040 RDI: ffff888059546f28
RBP: ffffc90000007c90 R08: ffffffff81ac83be R09: 1ffffffff203680e
R10: dffffc0000000000 R11: ffff8880465c3da0 R12: 1ffff92000000f78
R13: ffff888059546f28 R14: 0000000000000001 R15: 0000000000000100
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8880465c3da0 CR3: 0000000054b64000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
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 2b 8b 00       	call   0x8b2b96
   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

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/31 22:22 upstream 69e858e0b8b2 aa47157c .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: unable to handle kernel paging request in __run_timer_base
* Struck through repros no longer work on HEAD.