On Fri, 30 Sep 2022 04:23:23 +0200, Sabri N. Ferreiro wrote:

Hi,

When I used fuzz testing to test Linux kernel 6.0.0-rc6, the kernel triggered the following error: HEAD commit: 521a547ced6477c54b4b0cc206000406c221b4d6 git tree: upstream

Could you retest with 6.0-rc7 or later? A commit reverting the change might influence on the behavior significantly.

thanks,

Takashi

kernel config: https://pastebin.com/raw/hekxU61F console log: https://pastebin.com/KVwW9VQs

It seems that the fuzzer failed to extract any C reproducer, but I would so appreciate it if you have any idea how to solve this bug.

general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 1 PID: 29906 Comm: syz-executor.4 Not tainted 6.0.0-rc6+ #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:release_urb_ctx sound/usb/endpoint.c:97 [inline] RIP: 0010:release_urbs sound/usb/endpoint.c:1046 [inline] RIP: 0010:release_urbs+0x254/0x5a0 sound/usb/endpoint.c:1031 Code: 44 89 fe 48 c1 e0 08 4c 8b 74 03 58 e8 75 b4 53 fa 45 85 ff 0f 84 29 ff ff ff e8 07 b3 53 fa 49 8d 7e 68 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 32 03 00 00 49 8d 7e 60 49 8b 4e 68 48 89 f8 RSP: 0018:ffffc9001698f8d0 EFLAGS: 00010212 RAX: 000000000000000d RBX: ffff88805fc44000 RCX: 0000000000040000 RDX: ffffc900169d1000 RSI: ffff888018c21d40 RDI: 0000000000000068 RBP: 0000000000000000 R08: ffffffff87273539 R09: 0000000000000000 R10: 0000000000000005 R11: ffffed100bf88805 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000120 FS: 00007febd6e4e700(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555663ddc8 CR3: 0000000065e07000 CR4: 0000000000350ee0 Call Trace:

<TASK> snd_usb_endpoint_set_params+0x1aab/0x2550 snd_mask_min include/sound/pcm_params.h:49 [inline] params_format include/sound/pcm_params.h:315 [inline] snd_usb_hw_params+0x934/0x1180 sound/usb/pcm.c:503 snd_pcm_hw_params+0xbad/0x1da0 sound/core/pcm_native.c:767 snd_pcm_kernel_ioctl+0x164/0x310 sound/core/pcm_native.c:3437 snd_pcm_oss_change_params_locked+0x1834/0x3860 sound/core/oss/pcm_oss.c:976 snd_pcm_oss_change_params+0x76/0xd0 sound/core/oss/pcm_oss.c:1116 snd_pcm_oss_make_ready+0xb7/0x170 sound/core/oss/pcm_oss.c:1175 snd_pcm_oss_get_ptr sound/core/oss/pcm_oss.c:2208 [inline] snd_pcm_oss_ioctl+0x3cd/0x3270 sound/core/oss/pcm_oss.c:2729 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7febd66a80fd 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007febd6e4dbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007febd679c340 RCX: 00007febd66a80fd RDX: 00000000200000c0 RSI: 00000000800c5011 RDI: 0000000000000003 RBP: 00007febd6e4dc50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000005f R13: 00007ffc28c4cf7f R14: 00007ffc28c4d120 R15: 00007febd6e4dd80 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:release_urb_ctx sound/usb/endpoint.c:97 [inline] RIP: 0010:release_urbs sound/usb/endpoint.c:1046 [inline] RIP: 0010:release_urbs+0x254/0x5a0 sound/usb/endpoint.c:1031 Code: 44 89 fe 48 c1 e0 08 4c 8b 74 03 58 e8 75 b4 53 fa 45 85 ff 0f 84 29 ff ff ff e8 07 b3 53 fa 49 8d 7e 68 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 32 03 00 00 49 8d 7e 60 49 8b 4e 68 48 89 f8 RSP: 0018:ffffc9001698f8d0 EFLAGS: 00010212 RAX: 000000000000000d RBX: ffff88805fc44000 RCX: 0000000000040000 RDX: ffffc900169d1000 RSI: ffff888018c21d40 RDI: 0000000000000068 RBP: 0000000000000000 R08: ffffffff87273539 R09: 0000000000000000 R10: 0000000000000005 R11: ffffed100bf88805 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000120 FS: 00007febd6e4e700(0000) GS:ffff88807ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31424000 CR3: 0000000065e07000 CR4: 0000000000350ee0 ---------------- Code disassembly (best guess): 0: 44 89 fe mov %r15d,%esi 3: 48 c1 e0 08 shl $0x8,%rax 7: 4c 8b 74 03 58 mov 0x58(%rbx,%rax,1),%r14 c: e8 75 b4 53 fa callq 0xfa53b486 11: 45 85 ff test %r15d,%r15d 14: 0f 84 29 ff ff ff je 0xffffff43 1a: e8 07 b3 53 fa callq 0xfa53b326 1f: 49 8d 7e 68 lea 0x68(%r14),%rdi 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction 2f: 0f 85 32 03 00 00 jne 0x367 35: 49 8d 7e 60 lea 0x60(%r14),%rdi 39: 49 8b 4e 68 mov 0x68(%r14),%rcx 3d: 48 89 f8 mov %rdi,%rax