syzbot


KCSAN: data-race in __unmap_and_move / page_cache_delete_batch

Status: auto-closed as invalid on 2022/05/27 19:47
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 227d, last: 227d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __unmap_and_move / page_cache_delete_batch

write to 0xffffea00045cfd58 of 8 bytes by task 19446 on cpu 0:
 page_cache_delete_batch+0x1a7/0x470 mm/filemap.c:308
 delete_from_page_cache_batch+0x18f/0x2a0 mm/filemap.c:334
 truncate_inode_pages_range+0x3ca/0xae0 mm/truncate.c:370
 truncate_inode_pages mm/truncate.c:452 [inline]
 truncate_pagecache+0x4f/0x70 mm/truncate.c:753
 ext4_setattr+0x76c/0xa90 fs/ext4/inode.c:5485
 notify_change+0x9c3/0xa30 fs/attr.c:410
 do_truncate fs/open.c:65 [inline]
 do_sys_ftruncate+0x317/0x420 fs/open.c:193
 __do_sys_ftruncate fs/open.c:204 [inline]
 __se_sys_ftruncate fs/open.c:202 [inline]
 __x64_sys_ftruncate+0x2f/0x40 fs/open.c:202
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffea00045cfd58 of 8 bytes by task 19435 on cpu 1:
 __PageMovable include/linux/page-flags.h:661 [inline]
 __unmap_and_move+0xb1/0xb90 mm/migrate.c:923
 unmap_and_move+0x13c/0x950 mm/migrate.c:1102
 migrate_pages+0x28e/0x720 mm/migrate.c:1383
 do_mbind+0x79b/0x8b0 mm/mempolicy.c:1322
 kernel_mbind mm/mempolicy.c:1469 [inline]
 __do_sys_mbind mm/mempolicy.c:1547 [inline]
 __se_sys_mbind+0x13b/0x3f0 mm/mempolicy.c:1543
 __x64_sys_mbind+0x74/0x80 mm/mempolicy.c:1543
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff8881063aecc0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19435 Comm: syz-executor.4 Not tainted 5.18.0-rc3-syzkaller-00080-gd569e86915b7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/04/22 19:38 upstream d569e86915b7 131df97d .config log report info KCSAN: data-race in __unmap_and_move / page_cache_delete_batch
* Struck through repros no longer work on HEAD.