syzbot

loop4: detected capacity change from 0 to 2048
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
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BUG: KCSAN: data-race in file_update_time / inode_update_timestamps

write to 0xffff8881064f5844 of 4 bytes by task 4599 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1603 [inline]
 inode_update_timestamps+0x166/0x280 fs/inode.c:1962
 generic_update_time fs/inode.c:1997 [inline]
 inode_update_time fs/inode.c:2017 [inline]
 __file_update_time fs/inode.c:2206 [inline]
 file_update_time+0x229/0x2c0 fs/inode.c:2236
 ext4_page_mkwrite+0x1a4/0xb70 fs/ext4/inode.c:6132
 do_page_mkwrite mm/memory.c:3142 [inline]
 do_shared_fault mm/memory.c:5133 [inline]
 do_fault mm/memory.c:5195 [inline]
 do_pte_missing mm/memory.c:3947 [inline]
 handle_pte_fault mm/memory.c:5521 [inline]
 __handle_mm_fault mm/memory.c:5664 [inline]
 handle_mm_fault+0x1307/0x2940 mm/memory.c:5832
 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x296/0x650 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff8881064f5844 of 4 bytes by task 4600 on cpu 0:
 inode_get_mtime_nsec include/linux/fs.h:1589 [inline]
 inode_get_mtime include/linux/fs.h:1595 [inline]
 inode_needs_update_time fs/inode.c:2185 [inline]
 file_update_time+0x98/0x2c0 fs/inode.c:2232
 ext4_page_mkwrite+0x1a4/0xb70 fs/ext4/inode.c:6132
 do_page_mkwrite mm/memory.c:3142 [inline]
 do_shared_fault mm/memory.c:5133 [inline]
 do_fault mm/memory.c:5195 [inline]
 do_pte_missing mm/memory.c:3947 [inline]
 handle_pte_fault mm/memory.c:5521 [inline]
 __handle_mm_fault mm/memory.c:5664 [inline]
 handle_mm_fault+0x1307/0x2940 mm/memory.c:5832
 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x296/0x650 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
 rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:65
 copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
 copy_to_user_iter lib/iov_iter.c:25 [inline]
 iterate_ubuf include/linux/iov_iter.h:29 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
 iterate_and_advance include/linux/iov_iter.h:271 [inline]
 _copy_to_iter+0x137/0xb00 lib/iov_iter.c:185
 copy_to_iter include/linux/uio.h:196 [inline]
 get_random_bytes_user+0x112/0x260 drivers/char/random.c:464
 __do_sys_getrandom drivers/char/random.c:1406 [inline]
 __se_sys_getrandom drivers/char/random.c:1380 [inline]
 __x64_sys_getrandom+0xb5/0x190 drivers/char/random.c:1380
 x64_sys_call+0x2887/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:319
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x13d1a3ca -> 0x146a3a4a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4600 Comm: syz.4.228 Not tainted 6.11.0-rc3-syzkaller-00338-gc3f2d783a459 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
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