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KCSAN: data-race in bdev_set_nr_sectors / blkdev_llseek (2)

Status: auto-obsoleted due to no activity on 2024/03/30 06:54
Subsystems: block
[Documentation on labels]
Reported-by: syzbot+0d7b644aedafced2cab3@syzkaller.appspotmail.com
First crash: 52d, last: 52d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in bdev_set_nr_sectors / blkdev_llseek block 1 162d 127d 0/26 auto-obsoleted due to no activity on 2023/12/25 00:07

Sample crash report:
BUG: KCSAN: data-race in bdev_set_nr_sectors / blkdev_llseek

write to 0xffff888100630a30 of 8 bytes by task 4305 on cpu 1:
 i_size_write include/linux/fs.h:934 [inline]
 bdev_set_nr_sectors+0x42/0x70 block/bdev.c:427
 set_capacity block/genhd.c:61 [inline]
 set_capacity_and_notify+0x6e/0x170 block/genhd.c:74
 loop_set_size+0x2e/0x70 drivers/block/loop.c:235
 loop_configure+0xaf9/0xca0 drivers/block/loop.c:1096
 lo_ioctl+0x682/0x12e0
 blkdev_ioctl+0x375/0x460 block/ioctl.c:634
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888100630a30 of 8 bytes by task 901 on cpu 0:
 i_size_read include/linux/fs.h:912 [inline]
 blkdev_llseek+0x50/0x80 block/fops.c:533
 vfs_llseek fs/read_write.c:289 [inline]
 ksys_lseek fs/read_write.c:302 [inline]
 __do_sys_lseek fs/read_write.c:313 [inline]
 __se_sys_lseek fs/read_write.c:311 [inline]
 __x64_sys_lseek+0xe9/0x150 fs/read_write.c:311
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000000 -> 0x000000000005c000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 901 Comm: udevd Not tainted 6.8.0-rc5-syzkaller-00278-g603c04e27c3e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
blk_print_req_error: 2 callbacks suppressed
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/24 06:53 upstream 603c04e27c3e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in bdev_set_nr_sectors / blkdev_llseek
* Struck through repros no longer work on HEAD.