WARNING in isotp_tx_timer_handler

[Wei Chen]

Dear Linux Developer,

Recently when using our tool to fuzz kernel, the following crash was triggered:

HEAD commit: 4fe89d07 Linux v6.0
git tree: upstream
compiler: clang 12.0.0
console output:
https://drive.google.com/file/d/1uwGcdgsj0b2RQy0dQqiCN5ntcbYpVoKL/view?usp=sharing
Syzlang reproducer:
https://drive.google.com/file/d/1sWib_bzKTQCeQOqApX9y1wVJ0C-UdyJP/view?usp=sharing
kernel config: https://drive.google.com/file/d/1ZHRxVTXHL9mENdAPmQYS1DtgbflZ9XsD/view?usp=sharing

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: Wei Chen <harperchen1110@xxxxxxxxx>

WARNING: CPU: 0 PID: 0 at net/can/isotp.c:910 isotp_tx_timer_handler+0x160/0x270
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.0.0 #35
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:isotp_tx_timer_handler+0x160/0x270 net/can/isotp.c:910
Code: 01 00 00 00 00 00 48 81 c3 90 09 02 00 31 ed 48 89 df be 01 00
00 00 ba 01 00 00 00 31 c9 e8 07 62 2b f8 eb 6e e8 d0 15 4e f8 <0f> 0b
31 ed eb 63 e8 c5 15 4e f8 e8 70 75 3e f8 49 89 c6 49 81 c6
RSP: 0018:ffffc90000007c30 EFLAGS: 00010246
RAX: ffffffff89390350 RBX: ffff88804c440000 RCX: ffffffff8ccbb940
RDX: 0000000080000101 RSI: ffffffff8e13dba0 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000005 R09: ffffffff8939023d
R10: 0000000000000003 R11: ffffffff8ccbb940 R12: 1ffff1100988a0f5
R13: ffffffff8ccbc360 R14: ffff88804c4507a8 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88802cc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564e766615a8 CR3: 000000000cc8e000 CR4: 0000000000750ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x1b7/0x5d0 kernel/time/hrtimer.c:1766
 __do_softirq+0x372/0x783 kernel/softirq.c:571
 __irq_exit_rcu+0xcf/0x150 kernel/softirq.c:650
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:731
Code: fe ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 7c 93 4c 89 e7 e8 07
f5 a9 f7 eb 89 e8 00 41 fd ff 66 90 0f 00 2d 87 bc 5a 00 fb f4 <c3> 0f
1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8cc07da8 EFLAGS: 000002c2
RAX: 2a4c2150f0015f00 RBX: ffffffff8ccbb940 RCX: ffffffff8a2b46ee
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffffff8cc07ed0 R08: dffffc0000000000 R09: ffffed100598693d
R10: ffffed100598693d R11: 0000000000000000 R12: 1ffffffff1997728
R13: 1ffffffff1980fca R14: 0000000000000000 R15: dffffc0000000000
 default_idle_call+0x82/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x215/0x5e0 kernel/sched/idle.c:303
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
 rest_init+0x24f/0x270 init/main.c:727
 arch_call_rest_init+0xa/0xa
 start_kernel+0x490/0x536 init/main.c:1138
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0: ff 44 89 e1           incl   -0x1f(%rcx,%rcx,4)
   4: 80 e1 07             and    $0x7,%cl
   7: 80 c1 03             add    $0x3,%cl
   a: 38 c1                 cmp    %al,%cl
   c: 7c 93                 jl     0xffffffa1
   e: 4c 89 e7             mov    %r12,%rdi
  11: e8 07 f5 a9 f7       callq  0xf7a9f51d
  16: eb 89                 jmp    0xffffffa1
  18: e8 00 41 fd ff       callq  0xfffd411d
  1d: 66 90                 xchg   %ax,%ax
  1f: 0f 00 2d 87 bc 5a 00 verw   0x5abc87(%rip)        # 0x5abcad
  26: fb                   sti
  27: f4                   hlt
* 28: c3                   retq <-- trapping instruction
  29: 0f 1f 40 00           nopl   0x0(%rax)
  2d: 41 57                 push   %r15
  2f: 41 56                 push   %r14
  31: 53                   push   %rbx
  32: 49 be 00 00 00 00 00 movabs $0xdffffc0000000000,%r14
  39: fc ff df
  3c: 65                   gs
  3d: 48                   rex.W

Best,
Wei