Dear Linux Developer, Recently when using our tool to fuzz kernel, the following crash was triggered. The bug persists in the latest upstream v6.1-rc5. HEAD commit: 4fe89d07 Linux v6.0 git tree: upstream compiler: clang 12.0.0 console output: https://drive.google.com/file/d/1-hqsu5AQ5qqXwh8lZM0BTDfGPfR5ZZKQ/view?usp=share_link Syzlang reproducer: https://drive.google.com/file/d/1IsxrV9gGdgkM9sgLTy7k8ntYLDpwm7vZ/view?usp=share_link C reproducer: https://drive.google.com/file/d/1mS8bp9_OWNs_RS04UwzzZPU1IWwyKSSk/view?usp=share_link kernel config: https://drive.google.com/file/d/1ZHRxVTXHL9mENdAPmQYS1DtgbflZ9XsD/view?usp=sharing IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: Wei Chen <harperchen1110@xxxxxxxxx> general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 1 PID: 14835 Comm: syz-executor.1 Not tainted 6.0.0+ #39 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:az6027_i2c_xfer+0x1b6/0x1bb0 drivers/media/usb/dvb-usb/az6027.c:978 Code: 00 00 00 00 00 fc ff df 80 3c 08 00 74 12 48 89 df e8 7e 09 1b fb 48 b9 00 00 00 00 00 fc ff df 48 8b 1b 48 89 d8 48 c1 e8 03 <8a> 04 08 84 c0 0f 85 f0 16 00 00 44 0f b6 2b 48 8b 7c 24 20 31 f6 RSP: 0018:ffffc9000c907b20 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000010 RCX: dffffc0000000000 RDX: ffff88804f8ac880 RSI: 0000000000000099 RDI: 0000000000000099 RBP: ffff88801e381060 R08: ffffffff86bcdd1c R09: fffffbfff1c8dac6 R10: fffffbfff1c8dac6 R11: 0000000000000000 R12: ffff888021ce4400 R13: ffff88801e381060 R14: 0000000000000000 R15: 1ffff11003c7020c FS: 00007fd831ffe700(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd834ba5818 CR3: 000000007a775000 CR4: 0000000000750ee0 DR0: 0000000000000000 DR1: 000000000000000c DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> __i2c_transfer+0x77e/0x1930 drivers/i2c/i2c-core-base.c:2109 i2c_transfer+0x1d5/0x3d0 drivers/i2c/i2c-core-base.c:2170 i2cdev_ioctl_rdwr+0x393/0x660 drivers/i2c/i2c-dev.c:297 i2cdev_ioctl+0x75d/0x9f0 drivers/i2c/i2c-dev.c:458 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd834a8bded Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd831ffdc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd834babf80 RCX: 00007fd834a8bded RDX: 0000000020000300 RSI: 0000000000000707 RDI: 0000000000000003 RBP: 00007fd834af8ce0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd834babf80 R13: 00007fff5701981f R14: 00007fff570199c0 R15: 00007fd831ffddc0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:az6027_i2c_xfer+0x1b6/0x1bb0 drivers/media/usb/dvb-usb/az6027.c:978 Code: 00 00 00 00 00 fc ff df 80 3c 08 00 74 12 48 89 df e8 7e 09 1b fb 48 b9 00 00 00 00 00 fc ff df 48 8b 1b 48 89 d8 48 c1 e8 03 <8a> 04 08 84 c0 0f 85 f0 16 00 00 44 0f b6 2b 48 8b 7c 24 20 31 f6 RSP: 0018:ffffc9000c907b20 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000010 RCX: dffffc0000000000 RDX: ffff88804f8ac880 RSI: 0000000000000099 RDI: 0000000000000099 RBP: ffff88801e381060 R08: ffffffff86bcdd1c R09: fffffbfff1c8dac6 R10: fffffbfff1c8dac6 R11: 0000000000000000 R12: ffff888021ce4400 R13: ffff88801e381060 R14: 0000000000000000 R15: 1ffff11003c7020c FS: 00007fd831ffe700(0000) GS:ffff88802cc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa306d32000 CR3: 000000007a775000 CR4: 0000000000750ef0 DR0: 0000000000000000 DR1: 00000000fffff0fc DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 PKRU: 55555554 ---------------- Code disassembly (best guess), 7 bytes skipped: 0: df 80 3c 08 00 74 filds 0x7400083c(%rax) 6: 12 48 89 adc -0x77(%rax),%cl 9: df e8 fucomip %st(0),%st b: 7e 09 jle 0x16 d: 1b fb sbb %ebx,%edi f: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 16: fc ff df 19: 48 8b 1b mov (%rbx),%rbx 1c: 48 89 d8 mov %rbx,%rax 1f: 48 c1 e8 03 shr $0x3,%rax * 23: 8a 04 08 mov (%rax,%rcx,1),%al <-- trapping instruction 26: 84 c0 test %al,%al 28: 0f 85 f0 16 00 00 jne 0x171e 2e: 44 0f b6 2b movzbl (%rbx),%r13d 32: 48 8b 7c 24 20 mov 0x20(%rsp),%rdi 37: 31 f6 xor %esi,%esi Best, Wei
