syzbot


WARNING in try_to_migrate_one (3)

Status: upstream: reported C repro on 2025/08/09 20:36
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+63859a31071a369082b1@syzkaller.appspotmail.com
First crash: 22d, last: 18d
Cause bisection: introduced by (bisect log) :
commit cac1db8c3aad97d6ffb56ced8868d6cbbbd2bfbe
Author: Dev Jain <dev.jain@arm.com>
Date: Fri Jul 18 09:02:43 2025 +0000

  mm: optimize mprotect() by PTE batching

Crash: WARNING in try_to_migrate_one (log)
Repro: C syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] WARNING in try_to_migrate_one (3) 4 (10) 2025/08/11 06:34
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in try_to_migrate_one mm -1 1 761d 757d 0/29 auto-obsoleted due to no activity on 2023/11/06 07:16
upstream WARNING in try_to_migrate_one (2) mm -1 C error error 6 477d 537d 0/29 auto-obsoleted due to no activity on 2024/08/15 20:29
Last patch testing requests (5)
Created Duration User Patch Repo Result
2025/08/24 12:19 25m retest repro upstream OK log
2025/08/11 05:12 1h04m lorenzo.stoakes@oracle.com git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-hotfixes-unstable OK log
2025/08/10 06:06 52m hdanton@sina.com patch upstream report log
2025/08/10 02:02 52m hdanton@sina.com patch upstream report log
2025/08/10 01:36 18m hdanton@sina.com patch upstream report log

Sample crash report:
 do_initcall_level+0x104/0x190 init/main.c:1331
 do_initcalls+0x59/0xa0 init/main.c:1347
 kernel_init_freeable+0x334/0x4b0 init/main.c:1579
 kernel_init+0x1d/0x1d0 init/main.c:1469
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5866 at mm/rmap.c:2452 try_to_migrate_one+0xf27/0x34d0 mm/rmap.c:2451
Modules linked in:
CPU: 0 UID: 0 PID: 5866 Comm: syz-executor265 Not tainted 6.16.0-syzkaller-12187-g0227b49b5027 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:try_to_migrate_one+0xf27/0x34d0 mm/rmap.c:2451
Code: fb 00 00 00 f4 0f 84 35 0e 00 00 e8 f3 41 ae ff e9 73 f8 ff ff e8 e9 41 ae ff 4c 89 e7 48 c7 c6 00 79 96 8b e8 0a 92 16 ff 90 <0f> 0b 90 e9 60 ff ff ff e8 cc 41 ae ff 49 ff cf e9 3e fb ff ff e8
RSP: 0000:ffffc9000401f120 EFLAGS: 00010246
RAX: c3d51769d0dbd500 RBX: 0400000000000000 RCX: c3d51769d0dbd500
RDX: 0000000000000003 RSI: ffffffff8dba5e25 RDI: ffff8880115dda00
RBP: ffffc9000401f370 R08: ffff8880b8624253 R09: 1ffff110170c484a
R10: dffffc0000000000 R11: ffffed10170c484b R12: ffffea0001cd8000
R13: 0000000073603867 R14: dffffc0000000000 R15: ffffea0001cd8018
FS:  0000555590a54380(0000) GS:ffff888125c1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ad50 CR3: 00000000743ea000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rmap_walk_anon+0x550/0x730 mm/rmap.c:2842
 rmap_walk_locked mm/rmap.c:2958 [inline]
 try_to_migrate+0x3f5/0x670 mm/rmap.c:2619
 unmap_folio+0x191/0x1f0 mm/huge_memory.c:3137
 __folio_split+0x90d/0x1c60 mm/huge_memory.c:3711
 try_split_folio+0x13f/0x310 mm/migrate.c:1550
 migrate_pages_batch+0x653/0x3620 mm/migrate.c:1819
 migrate_pages_sync mm/migrate.c:1974 [inline]
 migrate_pages+0x1bcc/0x2930 mm/migrate.c:2083
 do_mbind mm/mempolicy.c:1539 [inline]
 kernel_mbind mm/mempolicy.c:1682 [inline]
 __do_sys_mbind mm/mempolicy.c:1756 [inline]
 __se_sys_mbind+0xa3e/0xc30 mm/mempolicy.c:1752
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb95004e539
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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:00007fffa7b144d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007fb95004e539
RDX: 0000000000000001 RSI: 0000000000600000 RDI: 0000200000000000
RBP: 00007fb9500c15f0 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/09 18:00 upstream 0227b49b5027 32a0e5ed .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in try_to_migrate_one
2025/08/09 16:44 upstream 0227b49b5027 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in try_to_migrate_one
2025/08/10 11:30 upstream 561c80369df0 32a0e5ed .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in try_to_migrate_one
2025/08/10 00:57 upstream c30a13538d9f 32a0e5ed .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in try_to_migrate_one
2025/08/05 20:31 upstream 7e161a991ea7 37880f40 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in try_to_migrate_one
* Struck through repros no longer work on HEAD.