syzbot


KCSAN: data-race in filemap_fault / set_capacity_and_notify

Status: auto-closed as invalid on 2021/12/03 09:38
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 403d, last: 403d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in filemap_fault / set_capacity_and_notify

write to 0xffff88810109fad0 of 8 bytes by task 11738 on cpu 0:
 i_size_write include/linux/fs.h:916 [inline]
 set_capacity block/genhd.c:59 [inline]
 set_capacity_and_notify+0xaa/0x200 block/genhd.c:73
 loop_set_size drivers/block/loop.c:298 [inline]
 loop_configure+0xcaa/0xeb0 drivers/block/loop.c:1297
 lo_ioctl+0x618/0x13e0
 blkdev_ioctl+0x1d0/0x3f0 block/ioctl.c:589
 block_ioctl+0x6e/0x80 block/fops.c:478
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810109fad0 of 8 bytes by task 11743 on cpu 1:
 i_size_read include/linux/fs.h:894 [inline]
 filemap_fault+0x8b/0x9f0 mm/filemap.c:3050
 __do_fault mm/memory.c:3858 [inline]
 do_shared_fault mm/memory.c:4227 [inline]
 do_fault mm/memory.c:4305 [inline]
 handle_pte_fault mm/memory.c:4559 [inline]
 __handle_mm_fault mm/memory.c:4694 [inline]
 handle_mm_fault+0xc81/0x1580 mm/memory.c:4792
 do_user_addr_fault+0x609/0xbe0 arch/x86/mm/fault.c:1397
 handle_page_fault arch/x86/mm/fault.c:1485 [inline]
 exc_page_fault+0x91/0x220 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x1e/0x30

value changed: 0x0000000000000000 -> 0x0000000000040e00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11743 Comm: syz-executor.5 Not tainted 5.15.0-rc7-syzkaller #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 2021/10/29 09:33 upstream f25a5481af12 2353a3ec .config log report info KCSAN: data-race in filemap_fault / set_capacity_and_notify
* Struck through repros no longer work on HEAD.