syzbot


BUG: unable to handle kernel NULL pointer dereference in compat_sys_recvmmsg_time32

Status: moderation: reported on 2025/08/18 16:32
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+aa8c78de89a49dadf2f5@syzkaller.appspotmail.com
First crash: 13d, last: 13d

Sample crash report:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 57252067 P4D 57252067 PUD 0 
Oops: Oops: 0002 [#1] SMP KASAN NOPTI
CPU: 2 UID: 0 PID: 11975 Comm: syz.3.2136 Not tainted 6.17.0-rc1-syzkaller-00038-g0cc53520e68b #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__x64_compat_sys_recvmmsg_time32+0x60/0x160 net/compat.c:414
Code: 4b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f8 00 00 00 48 8d 7b 60 48 8b 4b 38 48 b8 00 00 00 <00> 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b9 00 00 00
RSP: 0018:ffffc90000648c60 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc90000648ca8 RCX: ffffffff81a7e2fe
RDX: ffff88802e8f4880 RSI: ffffffff81a7df61 RDI: ffff888047ecec10
RBP: ffff888047ecec10 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff920000c918f
R13: 0000000080000102 R14: ffffffff898bf890 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880d68bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000004f6bc000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 __pfx_call_timer_fn+0x10/0x10 include/trace/events/timer.h:52
 </IRQ>
 <TASK>
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:__x64_compat_sys_recvmmsg_time32+0x60/0x160 net/compat.c:414
Code: 4b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f8 00 00 00 48 8d 7b 60 48 8b 4b 38 48 b8 00 00 00 <00> 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b9 00 00 00
RSP: 0018:ffffc90000648c60 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc90000648ca8 RCX: ffffffff81a7e2fe
RDX: ffff88802e8f4880 RSI: ffffffff81a7df61 RDI: ffff888047ecec10
RBP: ffff888047ecec10 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff920000c918f
R13: 0000000080000102 R14: ffffffff898bf890 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880d68bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000004f6bc000 CR4: 0000000000352ef0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/14 16:21 upstream 0cc53520e68b dcc075fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel NULL pointer dereference in compat_sys_recvmmsg_time32
* Struck through repros no longer work on HEAD.