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
