================================================================== BUG: KCSAN: data-race in copy_page_to_iter / fat16_ent_put write to 0xffff888126cc5588 of 2 bytes by task 24319 on cpu 1: fat16_ent_put+0x24/0x50 fs/fat/fatent.c:182 fat_alloc_clusters+0x47d/0xa80 fs/fat/fatent.c:502 fat_add_cluster fs/fat/inode.c:108 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x263/0x600 fs/fat/inode.c:190 __block_write_begin_int+0x33d/0xc90 fs/buffer.c:2006 __block_write_begin fs/buffer.c:2056 [inline] block_write_begin+0x77/0x170 fs/buffer.c:2117 cont_write_begin+0x3cf/0x500 fs/buffer.c:2463 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 pagecache_write_begin+0x5a/0x70 mm/filemap.c:3631 cont_expand_zero fs/buffer.c:2390 [inline] cont_write_begin+0x17e/0x500 fs/buffer.c:2453 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 pagecache_write_begin+0x5a/0x70 mm/filemap.c:3631 generic_cont_expand_simple+0x90/0x120 fs/buffer.c:2355 fat_cont_expand+0x3a/0x160 fs/fat/file.c:223 fat_setattr+0x34a/0x880 fs/fat/file.c:504 notify_change+0x9c3/0xa30 fs/attr.c:410 do_truncate fs/open.c:65 [inline] do_sys_ftruncate+0x317/0x420 fs/open.c:193 __do_sys_ftruncate fs/open.c:204 [inline] __se_sys_ftruncate fs/open.c:202 [inline] __x64_sys_ftruncate+0x2f/0x40 fs/open.c:202 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+0x44/0xae read to 0xffff888126cc5000 of 4096 bytes by task 4611 on cpu 0: instrument_copy_to_user include/linux/instrumented.h:119 [inline] copyout lib/iov_iter.c:154 [inline] copy_page_to_iter_iovec lib/iov_iter.c:226 [inline] __copy_page_to_iter lib/iov_iter.c:852 [inline] copy_page_to_iter+0x415/0x7b0 lib/iov_iter.c:880 copy_folio_to_iter include/linux/uio.h:153 [inline] filemap_read+0x10b2/0x1400 mm/filemap.c:2730 blkdev_read_iter+0x2c6/0x370 block/fops.c:611 call_read_iter include/linux/fs.h:2044 [inline] new_sync_read fs/read_write.c:401 [inline] vfs_read+0x5a5/0x6a0 fs/read_write.c:482 ksys_read+0xe8/0x1a0 fs/read_write.c:620 __do_sys_read fs/read_write.c:630 [inline] __se_sys_read fs/read_write.c:628 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:628 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+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 4611 Comm: udevd Not tainted 5.18.0-rc6-syzkaller-00153-g2fe1020d73ca-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ================================================================== I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop3, sector 262016 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop3, sector 262016 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop3, sector 262016 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 Buffer I/O error on dev loop3, logical block 32752, async page read I/O error, dev loop0, sector 264064 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0