KCSAN: data-race in bdev_set_nr_sectors / blkdev

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in bdev_set_nr_sectors / blkdev_llseek (2) block				1	75d	75d	0/26	auto-obsoleted due to no activity on 2024/03/30 06:54

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BUG: KCSAN: data-race in bdev_set_nr_sectors / blkdev_llseek

write to 0xffff8881004c0a30 of 8 bytes by task 19178 on cpu 0:
 i_size_write include/linux/fs.h:932 [inline]
 bdev_set_nr_sectors+0x42/0x70 block/bdev.c:421
 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:237
 loop_configure+0xaf9/0xca0 drivers/block/loop.c:1100
 lo_ioctl+0x682/0x12e0
 blkdev_ioctl+0x375/0x460 block/ioctl.c:633
 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:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881004c0a30 of 8 bytes by task 30570 on cpu 1:
 i_size_read include/linux/fs.h:910 [inline]
 blkdev_llseek+0x50/0x80 block/fops.c:518
 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:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000000 -> 0x0000000000014800

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30570 Comm: udevd Not tainted 6.6.0-syzkaller-14614-g77fa2fbe87fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2