syzbot


general protection fault in zap_huge_pmd

Status: upstream: reported C repro on 2026/03/18 15:03
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+de14f7701c22477db718@syzkaller.appspotmail.com
First crash: 30d, last: 26d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] general protection fault in zap_huge_pmd 9 (10) 2026/03/19 10:04
Last patch testing requests (8)
Created Duration User Patch Repo Result
2026/04/03 03:24 23m retest repro linux-next OK log
2026/04/03 03:24 2h24m retest repro linux-next OK log
2026/04/03 03:24 2h15m retest repro linux-next OK log
2026/04/03 03:24 1h06m retest repro linux-next OK log
2026/04/03 03:24 54m retest repro linux-next OK log
2026/03/17 04:19 39m avagin@google.com patch linux-next OK log
2026/03/16 01:22 32m avagin@google.com patch linux-next OK log
2026/03/15 20:36 59m avagin@google.com patch linux-next report log

Sample crash report:
pci 0000:00:05.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=io+mem:owns=io+mem
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 UID: 0 PID: 12938 Comm: syz.1.2092 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:folio_test_anon include/linux/page-flags.h:718 [inline]
RIP: 0010:zap_huge_pmd+0x7b1/0x1030 mm/huge_memory.c:2463
Code: 08 00 00 e8 81 ca 92 ff 48 c7 44 24 10 00 00 00 00 4c 8b 3c 24 4c 8d 75 18 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 f7 e8 f1 43 fc ff 49 8b 1e 48 89 de 48 83
RSP: 0018:ffffc90005817310 EFLAGS: 00010206
RAX: 0000000000000003 RBX: f000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 0000000000000000 R08: ffff888035a1b02f R09: 1ffff11006b43605
R10: dffffc0000000000 R11: ffffed1006b43606 R12: ffff888035a1b028
R13: fffffffffffffa00 R14: 0000000000000018 R15: ffffc90005817880
FS:  0000000000000000(0000) GS:ffff888124ee1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3b6b28 CR3: 000000000e94a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 zap_pmd_range mm/memory.c:1990 [inline]
 zap_pud_range mm/memory.c:2032 [inline]
 zap_p4d_range mm/memory.c:2053 [inline]
 __zap_vma_range+0xa82/0x4bd0 mm/memory.c:2093
 unmap_vmas+0x379/0x530 mm/memory.c:2162
 exit_mmap+0x280/0xa10 mm/mmap.c:1302
 __mmput+0x118/0x430 kernel/fork.c:1180
 exit_mm+0x18e/0x250 kernel/exit.c:581
 do_exit+0x8b9/0x2490 kernel/exit.c:962
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1116
 get_signal+0x1284/0x1330 kernel/signal.c:3036
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:269 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd80039c799
Code: Unable to access opcode bytes at 0x7fd80039c76f.
RSP: 002b:00007fd8012fc0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fd800615fa8 RCX: 00007fd80039c799
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd800615fa8
RBP: 00007fd800615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd800616038 R14: 00007ffea343f6b0 R15: 00007ffea343f798
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:folio_test_anon include/linux/page-flags.h:718 [inline]
RIP: 0010:zap_huge_pmd+0x7b1/0x1030 mm/huge_memory.c:2463
Code: 08 00 00 e8 81 ca 92 ff 48 c7 44 24 10 00 00 00 00 4c 8b 3c 24 4c 8d 75 18 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 f7 e8 f1 43 fc ff 49 8b 1e 48 89 de 48 83
RSP: 0018:ffffc90005817310 EFLAGS: 00010206
RAX: 0000000000000003 RBX: f000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 0000000000000000 R08: ffff888035a1b02f R09: 1ffff11006b43605
R10: dffffc0000000000 R11: ffffed1006b43606 R12: ffff888035a1b028
R13: fffffffffffffa00 R14: 0000000000000018 R15: ffffc90005817880
FS:  0000000000000000(0000) GS:ffff888124ee1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3b6b28 CR3: 000000000e94a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	08 00                	or     %al,(%rax)
   2:	00 e8                	add    %ch,%al
   4:	81 ca 92 ff 48 c7    	or     $0xc748ff92,%edx
   a:	44 24 10             	rex.R and $0x10,%al
   d:	00 00                	add    %al,(%rax)
   f:	00 00                	add    %al,(%rax)
  11:	4c 8b 3c 24          	mov    (%rsp),%r15
  15:	4c 8d 75 18          	lea    0x18(%rbp),%r14
  19:	4c 89 f0             	mov    %r14,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 f7             	mov    %r14,%rdi
  33:	e8 f1 43 fc ff       	call   0xfffc4429
  38:	49 8b 1e             	mov    (%r14),%rbx
  3b:	48 89 de             	mov    %rbx,%rsi
  3e:	48                   	rex.W
  3f:	83                   	.byte 0x83

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/20 02:35 linux-next 8e42d2514a7e bd6dcb30 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
2026/03/15 22:47 linux-next b84a0ebe421c ee8d34d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
2026/03/15 21:30 linux-next b84a0ebe421c ee8d34d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
2026/03/15 20:28 linux-next b84a0ebe421c ee8d34d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
2026/03/15 19:23 linux-next b84a0ebe421c ee8d34d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
2026/03/15 18:11 linux-next b84a0ebe421c ee8d34d6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
2026/03/15 16:54 linux-next b84a0ebe421c ee8d34d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce general protection fault in zap_huge_pmd
* Struck through repros no longer work on HEAD.