syzbot

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BUG: KCSAN: data-race in force_page_cache_ra / set_capacity_and_notify

write to 0xffff8881005d44c0 of 8 bytes by task 4610 on cpu 0:
 i_size_write include/linux/fs.h:871 [inline]
 set_capacity block/genhd.c:48 [inline]
 set_capacity_and_notify+0xaa/0x1c0 block/genhd.c:62
 loop_set_size drivers/block/loop.c:255 [inline]
 loop_configure+0xafc/0xcb0 drivers/block/loop.c:1162
 lo_ioctl+0x555/0x11f0 drivers/block/loop.c:1690
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1662
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881005d44c0 of 8 bytes by task 4605 on cpu 1:
 i_size_read include/linux/fs.h:849 [inline]
 do_page_cache_ra mm/readahead.c:254 [inline]
 force_page_cache_ra+0x1cf/0x280 mm/readahead.c:299
 force_page_cache_readahead mm/internal.h:59 [inline]
 generic_fadvise+0x387/0x5d0 mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:186 [inline]
 ksys_fadvise64_64 mm/fadvise.c:200 [inline]
 __do_sys_fadvise64 mm/fadvise.c:215 [inline]
 __se_sys_fadvise64 mm/fadvise.c:213 [inline]
 __x64_sys_fadvise64+0xc5/0x100 mm/fadvise.c:213
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4605 Comm: syz-executor.1 Not tainted 5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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