syzbot


WARNING in untrack_pfn (2)

Status: upstream: reported C repro on 2023/09/04 06:46
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+2b0bae3d3650486d7c7d@syzkaller.appspotmail.com
First crash: 833d, last: 14d
Fix commit to backport (bisect log) :
tree: upstream
commit d155df53f31068c3340733d586eb9b3ddfd70fc5
Author: Ma Wupeng <mawupeng1@huawei.com>
Date: Fri Feb 17 02:56:15 2023 +0000

  x86/mm/pat: clear VM_PAT if copy_p4d_range failed

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: WARNING in untrack_pfn (log)
Repro: C syz .config
  
Bug presence (2)
Date Name Commit Repro Result
2023/09/04 linux-6.1.y (ToT) c2cbfe5f5122 C [report] WARNING in untrack_pfn
2023/09/04 upstream (ToT) 708283abf896 C Didn't crash
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in untrack_pfn kernel -1 C done error 128 630d 2702d 0/29 auto-obsoleted due to no activity on 2024/07/03 15:42
android-49 WARNING in untrack_pfn -1 syz 35 2204d 2437d 0/3 public: reported syz repro on 2019/04/14 09:28
linux-5.15 WARNING in untrack_pfn origin:lts-only -1 C done 10 7d11h 880d 0/3 upstream: reported C repro on 2023/07/19 07:05
linux-4.19 WARNING in untrack_pfn -1 C error 24 1063d 2324d 0/1 upstream: reported C repro on 2019/08/05 09:38
android-6-12 WARNING in untrack_pfn origin:downstream -1 C 7 32d 179d 0/1 premoderation: reported C repro on 2025/06/19 03:53
linux-4.14 WARNING in untrack_pfn -1 C inconclusive 27 1055d 2316d 0/1 upstream: reported C repro on 2019/08/13 08:40
android-44 WARNING in untrack_pfn -1 C 211 2469d 2843d 0/2 closed as invalid on 2019/03/16 01:21
android-414 WARNING in untrack_pfn -1 syz 1 2549d 2438d 0/1 public: reported syz repro on 2019/04/13 00:01
linux-6.1 WARNING in untrack_pfn -1 2 967d 975d 0/3 auto-obsoleted due to no activity on 2023/08/21 02:48
android-44 WARNING in untrack_pfn (2) -1 C 71 2203d 2440d 0/2 public: reported C repro on 2019/04/11 08:44
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/05/11 12:18 5m kevinpaul468@gmail.com patch linux-6.1.y error
Fix bisection attempts (3)
Created Duration User Patch Repo Result
2023/12/09 09:32 4h54m fix candidate upstream OK (1) job log
2023/11/17 15:10 1h04m bisect fix linux-6.1.y OK (0) job log log
2023/10/16 13:28 1h39m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
RDX: 0000000006000009 RSI: 0000000000001000 RDI: 0000200000ffb000
RBP: 00007ffc9320eb30 R08: 0000000000000003 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f1f955e5fa0 R14: 00007f1f955e5fa0 R15: 0000000000000006
 </TASK>
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4429 at arch/x86/mm/pat/memtype.c:1028 get_pat_info arch/x86/mm/pat/memtype.c:1028 [inline]
WARNING: CPU: 1 PID: 4429 at arch/x86/mm/pat/memtype.c:1028 untrack_pfn+0x386/0x400 arch/x86/mm/pat/memtype.c:1130
Modules linked in:
CPU: 1 PID: 4429 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:get_pat_info arch/x86/mm/pat/memtype.c:1028 [inline]
RIP: 0010:untrack_pfn+0x386/0x400 arch/x86/mm/pat/memtype.c:1130
Code: 45 85 e4 49 bd 00 00 00 00 00 fc ff df 74 71 e8 a0 8e 46 00 4c 8b 64 24 10 4d 85 e4 75 ac e8 91 8e 46 00 eb 11 e8 8a 8e 46 00 <0f> 0b 49 bd 00 00 00 00 00 fc ff df 48 c7 44 24 20 0e 36 e0 45 4a
RSP: 0018:ffffc90003377560 EFLAGS: 00010293
RAX: ffffffff813a47d6 RBX: 1ffff9200066eeb0 RCX: ffff88802f263b80
RDX: 0000000000000000 RSI: 0000000000000028 RDI: 0000000000000020
RBP: ffffc90003377658 R08: ffffc900033775e0 R09: fffffbfff1c3ed56
R10: fffffbfff1c3ed56 R11: 1ffffffff1c3ed55 R12: ffff88801d3e2458
R13: ffff88801d3e2438 R14: 0000000000000028 R15: 00000000ffffffea
FS:  0000555563737500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c3e86f4580 CR3: 000000001efbe000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 unmap_single_vma+0x1df/0x290 mm/memory.c:1669
 zap_page_range_single+0x37d/0x460 mm/memory.c:1794
 remap_pfn_range_notrack+0x9f4/0xa60 mm/memory.c:2553
 remap_pfn_range+0xed/0x160 mm/memory.c:2578
 call_mmap include/linux/fs.h:2270 [inline]
 mmap_file+0x5d/0xb0 mm/util.c:1109
 __mmap_region mm/mmap.c:2772 [inline]
 mmap_region+0xe2c/0x1c70 mm/mmap.c:2916
 do_mmap+0x958/0xfd0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1f9538f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc9320ead8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f1f955e5fa0 RCX: 00007f1f9538f749
RDX: 0000000006000009 RSI: 0000000000001000 RDI: 0000200000ffb000
RBP: 00007ffc9320eb30 R08: 0000000000000003 R09: 0000000100000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f1f955e5fa0 R14: 00007f1f955e5fa0 R15: 0000000000000006
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/01 08:27 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in untrack_pfn
2023/09/04 06:46 linux-6.1.y c2cbfe5f5122 696ea0d2 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in untrack_pfn
2025/12/01 08:02 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in untrack_pfn
2024/01/05 19:08 linux-6.1.y 38fb82ecd144 28c42cff .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in untrack_pfn
2023/11/21 04:02 linux-6.1.y 69e434a1cb21 cb976f63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in untrack_pfn
2023/09/11 02:56 linux-6.1.y 59b13c2b647e 6654cf89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING in untrack_pfn
* Struck through repros no longer work on HEAD.