syzbot


general protection fault in generic_hwtstamp_ioctl_lower

Status: fixed on 2023/10/12 12:48
Subsystems: net
[Documentation on labels]
Fix commit: c35e927cbe09 net: omit ndo_hwtstamp_get() call when possible in dev_set_hwtstamp_phylib()
First crash: 294d, last: 291d
Cause bisection: introduced by (bisect log) :
commit fd770e856e226f80fe6e1dc9d1861bcb135cdf0b
Author: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Tue Aug 1 14:28:24 2023 +0000

  net: remove phy_has_hwtstamp() -> phy_mii_ioctl() decision from converted drivers

Crash: BUG: unable to handle kernel NULL pointer dereference in generic_hwtstamp_ioctl_lower (log)
Repro: C syz .config
  

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 PID: 5039 Comm: syz-executor917 Not tainted 6.5.0-rc4-next-20230804-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
RIP: 0010:generic_hwtstamp_ioctl_lower+0xf7/0x3c0 net/core/dev_ioctl.c:419
Code: 24 08 48 c1 e8 03 42 80 3c 30 00 0f 85 ad 02 00 00 48 ba 00 00 00 00 00 fc ff df 4d 8b 75 10 49 8d 7e 10 48 89 f8 48 c1 e8 03 <0f> b6 0c 10 49 8d 46 27 48 89 c6 83 e0 07 48 c1 ee 03 0f b6 14 16
RSP: 0018:ffffc90003a7f790 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff888027174000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8422693b RDI: 0000000000000010
RBP: ffffc90003a7f880 R08: 0000000000000006 R09: 0000000000000003
R10: ffffc90003a7f7eb R11: 0000000000094000 R12: 1ffff9200074fef6
R13: ffffc90003a7f8f0 R14: 0000000000000000 R15: ffffffff8b9f4300
FS:  000055555640b380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 0000000073353000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 generic_hwtstamp_get_lower net/core/dev_ioctl.c:443 [inline]
 generic_hwtstamp_get_lower+0xe4/0x120 net/core/dev_ioctl.c:431
 dev_set_hwtstamp_phylib+0x3ae/0x620 net/core/dev_ioctl.c:338
 dev_set_hwtstamp+0x413/0x5b0 net/core/dev_ioctl.c:395
 dev_ifsioc+0x629/0x1090 net/core/dev_ioctl.c:597
 dev_ioctl+0x224/0x1090 net/core/dev_ioctl.c:783
 sock_do_ioctl+0x1fc/0x290 net/socket.c:1206
 sock_ioctl+0x205/0x6d0 net/socket.c:1309
 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+0x18f/0x210 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f8466771419
Code: 48 83 c4 28 c3 e8 d7 19 00 00 0f 1f 80 00 00 00 00 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:00007ffc3b8379e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f84667be390 RCX: 00007f8466771419
RDX: 0000000020000080 RSI: 00000000000089b0 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000555500000000 R09: 0000555500000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc3b837a30
R13: 00007ffc3b837a00 R14: 0000000000000001 R15: 00007ffc3b837a30
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_hwtstamp_ioctl_lower+0xf7/0x3c0 net/core/dev_ioctl.c:419
Code: 24 08 48 c1 e8 03 42 80 3c 30 00 0f 85 ad 02 00 00 48 ba 00 00 00 00 00 fc ff df 4d 8b 75 10 49 8d 7e 10 48 89 f8 48 c1 e8 03 <0f> b6 0c 10 49 8d 46 27 48 89 c6 83 e0 07 48 c1 ee 03 0f b6 14 16
RSP: 0018:ffffc90003a7f790 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff888027174000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8422693b RDI: 0000000000000010
RBP: ffffc90003a7f880 R08: 0000000000000006 R09: 0000000000000003
R10: ffffc90003a7f7eb R11: 0000000000094000 R12: 1ffff9200074fef6
R13: ffffc90003a7f8f0 R14: 0000000000000000 R15: ffffffff8b9f4300
FS:  000055555640b380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc9a12e198 CR3: 0000000073353000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	24 08                	and    $0x8,%al
   2:	48 c1 e8 03          	shr    $0x3,%rax
   6:	42 80 3c 30 00       	cmpb   $0x0,(%rax,%r14,1)
   b:	0f 85 ad 02 00 00    	jne    0x2be
  11:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  18:	fc ff df
  1b:	4d 8b 75 10          	mov    0x10(%r13),%r14
  1f:	49 8d 7e 10          	lea    0x10(%r14),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 0c 10          	movzbl (%rax,%rdx,1),%ecx <-- trapping instruction
  2e:	49 8d 46 27          	lea    0x27(%r14),%rax
  32:	48 89 c6             	mov    %rax,%rsi
  35:	83 e0 07             	and    $0x7,%eax
  38:	48 c1 ee 03          	shr    $0x3,%rsi
  3c:	0f b6 14 16          	movzbl (%rsi,%rdx,1),%edx

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/04 08:38 linux-next bdffb18b5dd8 74621247 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
2023/08/07 01:54 linux-next bdffb18b5dd8 4ffcc9ef .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
2023/08/05 21:54 linux-next bdffb18b5dd8 4ffcc9ef .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
2023/08/04 07:16 linux-next bdffb18b5dd8 74621247 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
2023/08/04 06:58 linux-next bdffb18b5dd8 74621247 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
2023/08/04 06:45 linux-next bdffb18b5dd8 74621247 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
2023/08/04 06:39 linux-next bdffb18b5dd8 74621247 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in generic_hwtstamp_ioctl_lower
* Struck through repros no longer work on HEAD.