syzbot


general protection fault in pick_next_entity

Status: moderation: reported on 2026/05/10 20:40
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+d3bd77932b0f5df02c46@syzkaller.appspotmail.com
First crash: 6d10h, last: 6d10h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in enqueue_entity kernel 7 3 1547d 1588d 0/29 auto-closed as invalid on 2022/05/17 04:41

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 0 UID: 0 PID: 7450 Comm: syz.3.519 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:pick_next_entity+0xca8/0xe90 kernel/sched/fair.c:5757
Code: 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 bd ea 97 00 4c 3b 33 79 05 48 8b 6c 24 40 48 8d 5d 59 48 89 d8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 75 61 80 3b 00 74 14 48 8b 7c 24 70 48 89 ee
RSP: 0018:ffffc9000594f1d0 EFLAGS: 00010002
RAX: 000000000000000b RBX: 0000000000000059 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880b863af00 RDI: ffff8880b863af50
RBP: 0000000000000000 R08: ffff88807c081ec7 R09: 1ffff1100f8103d8
R10: dffffc0000000000 R11: ffffed100f8103d9 R12: dffffc0000000000
R13: ffff8880b863af00 R14: 0000000000000000 R15: ffff8880b863af01
FS:  0000555594831500(0000) GS:ffff888125290000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001e80 CR3: 0000000075766000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 wakeup_preempt_fair+0x7a4/0xb60 kernel/sched/fair.c:9141
 wakeup_preempt+0x162/0x300 kernel/sched/core.c:2248
 attach_task kernel/sched/sched.h:3035 [inline]
 attach_tasks kernel/sched/fair.c:10026 [inline]
 sched_balance_rq+0x42c4/0x5a60 kernel/sched/fair.c:12164
 sched_balance_newidle kernel/sched/fair.c:13239 [inline]
 pick_next_task_fair+0xb3f/0x1ab0 kernel/sched/fair.c:9267
 __pick_next_task+0xe6/0x480 kernel/sched/core.c:6019
 pick_next_task kernel/sched/core.c:-1 [inline]
 __schedule+0x974/0x5680 kernel/sched/core.c:7105
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 do_nanosleep+0x1c2/0x620 kernel/time/hrtimer.c:2293
 hrtimer_nanosleep+0x18f/0x3a0 kernel/time/hrtimer.c:2339
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1391 [inline]
 __se_sys_clock_nanosleep+0x35b/0x3b0 kernel/time/posix-timers.c:1368
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb2cc15d60e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fb2cc53fb28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555594831500 RCX: 00007fb2cc15d60e
RDX: 00007fb2cc53fb80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fb2cc417da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000002fa01
R13: 00007fb2cc415fac R14: 000000000002ee7a R15: 00007fb2cc415fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pick_next_entity+0xca8/0xe90 kernel/sched/fair.c:5757
Code: 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 bd ea 97 00 4c 3b 33 79 05 48 8b 6c 24 40 48 8d 5d 59 48 89 d8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 75 61 80 3b 00 74 14 48 8b 7c 24 70 48 89 ee
RSP: 0018:ffffc9000594f1d0 EFLAGS: 00010002
RAX: 000000000000000b RBX: 0000000000000059 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880b863af00 RDI: ffff8880b863af50
RBP: 0000000000000000 R08: ffff88807c081ec7 R09: 1ffff1100f8103d8
R10: dffffc0000000000 R11: ffffed100f8103d9 R12: dffffc0000000000
R13: ffff8880b863af00 R14: 0000000000000000 R15: ffff8880b863af01
FS:  0000555594831500(0000) GS:ffff888125290000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001e80 CR3: 0000000075766000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	89 d8                	mov    %ebx,%eax
   2:	48 c1 e8 03          	shr    $0x3,%rax
   6:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
   b:	74 08                	je     0x15
   d:	48 89 df             	mov    %rbx,%rdi
  10:	e8 bd ea 97 00       	call   0x97ead2
  15:	4c 3b 33             	cmp    (%rbx),%r14
  18:	79 05                	jns    0x1f
  1a:	48 8b 6c 24 40       	mov    0x40(%rsp),%rbp
  1f:	48 8d 5d 59          	lea    0x59(%rbp),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	75 61                	jne    0x94
  33:	80 3b 00             	cmpb   $0x0,(%rbx)
  36:	74 14                	je     0x4c
  38:	48 8b 7c 24 70       	mov    0x70(%rsp),%rdi
  3d:	48 89 ee             	mov    %rbp,%rsi

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/06 20:35 upstream 74fe02ce122a cbcd9ea0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce general protection fault in pick_next_entity
* Struck through repros no longer work on HEAD.