syzbot


KCSAN: data-race in mprotect_fixup / remove_migration_pte

Status: moderation: reported on 2024/11/21 20:28
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+61e70862ec7c46649940@syzkaller.appspotmail.com
First crash: 4d17h, last: 4d17h

Sample crash report:
loop0: detected capacity change from 0 to 128
==================================================================
BUG: KCSAN: data-race in mprotect_fixup / remove_migration_pte

write to 0xffff888116501d40 of 8 bytes by task 12575 on cpu 0:
 vm_flags_init include/linux/mm.h:874 [inline]
 vm_flags_reset include/linux/mm.h:886 [inline]
 mprotect_fixup+0x419/0x5e0 mm/mprotect.c:677
 do_mprotect_pkey+0x653/0x960 mm/mprotect.c:838
 __do_sys_mprotect mm/mprotect.c:859 [inline]
 __se_sys_mprotect mm/mprotect.c:856 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:856
 x64_sys_call+0x2770/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888116501d40 of 8 bytes by task 12569 on cpu 1:
 remove_migration_pte+0x678/0x9c0 mm/migrate.c:339
 rmap_walk_anon+0x28f/0x440 mm/rmap.c:2635
 rmap_walk+0x5b/0x70 mm/rmap.c:2713
 remove_migration_ptes mm/migrate.c:373 [inline]
 migrate_folio_move mm/migrate.c:1388 [inline]
 migrate_pages_batch+0x1374/0x1910 mm/migrate.c:1898
 migrate_pages_sync mm/migrate.c:1964 [inline]
 migrate_pages+0xff1/0x1820 mm/migrate.c:2073
 do_mbind mm/mempolicy.c:1390 [inline]
 kernel_mbind mm/mempolicy.c:1533 [inline]
 __do_sys_mbind mm/mempolicy.c:1607 [inline]
 __se_sys_mbind+0xf76/0x1160 mm/mempolicy.c:1603
 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1603
 x64_sys_call+0x2662/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:238
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000102077 -> 0x0000000000102071

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12569 Comm: syz.0.2894 Not tainted 6.12.0-syzkaller-03657-g43fb83c17ba2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/21 20:28 upstream 43fb83c17ba2 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mprotect_fixup / remove_migration_pte
* Struck through repros no longer work on HEAD.