syzbot

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BUG: KCSAN: data-race in bdev_disk_changed / set_capacity_and_notify

write to 0xffff8881023be6c8 of 8 bytes by task 24040 on cpu 1:
 set_capacity block/genhd.c:64 [inline]
 set_capacity_and_notify+0xab/0x1d0 block/genhd.c:78
 loop_set_size+0x2e/0x70 drivers/block/loop.c:237
 loop_configure+0xb1b/0xc30 drivers/block/loop.c:1100
 lo_ioctl+0x641/0x1290
 blkdev_ioctl+0x20e/0x440 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 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+0x63/0xcd

read to 0xffff8881023be6c8 of 8 bytes by task 2141 on cpu 0:
 bdev_nr_sectors include/linux/blkdev.h:789 [inline]
 get_capacity include/linux/blkdev.h:799 [inline]
 bdev_disk_changed+0x1d9/0xbf0 block/partitions/core.c:687
 blkdev_get_whole+0x256/0x270 block/bdev.c:685
 blkdev_get_by_dev+0x248/0x650 block/bdev.c:822
 blkdev_open+0xac/0x140 block/fops.c:485
 do_dentry_open+0x59a/0x910 fs/open.c:882
 vfs_open+0x43/0x50 fs/open.c:1013
 do_open fs/namei.c:3557 [inline]
 path_openat+0x169d/0x1b00 fs/namei.c:3713
 do_filp_open+0x105/0x220 fs/namei.c:3740
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1337
 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+0x63/0xcd

value changed: 0x0000000000000000 -> 0x0000000000040800

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2141 Comm: udevd Not tainted 6.1.0-rc4-syzkaller-00294-geb037f16f7e8-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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