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BUG: KCSAN: data-race in generic_fillattr / inode_add_bytes

read-write to 0xffff8881049adef0 of 8 bytes by task 4775 on cpu 0:
 __inode_add_bytes fs/stat.c:907 [inline]
 inode_add_bytes+0x47/0xe0 fs/stat.c:920
 __dquot_alloc_space+0x17d/0x890 fs/quota/dquot.c:1652
 dquot_alloc_space_nodirty include/linux/quotaops.h:292 [inline]
 dquot_alloc_block_nodirty include/linux/quotaops.h:319 [inline]
 shmem_inode_acct_blocks+0x125/0x230 mm/shmem.c:237
 shmem_alloc_and_add_folio mm/shmem.c:2008 [inline]
 shmem_get_folio_gfp+0x5d3/0xd90 mm/shmem.c:2531
 shmem_get_folio mm/shmem.c:2637 [inline]
 shmem_write_begin+0xfc/0x1f0 mm/shmem.c:3268
 generic_perform_write+0x186/0x490 mm/filemap.c:4374
 shmem_file_write_iter+0xc5/0xf0 mm/shmem.c:3443
 __kernel_write_iter+0x30f/0x590 fs/read_write.c:621
 dump_emit_page fs/coredump.c:1293 [inline]
 dump_user_range+0xa73/0xd00 fs/coredump.c:1367
 elf_core_dump+0x21c0/0x2340 fs/binfmt_elf.c:2106
 coredump_write+0xafb/0xdd0 fs/coredump.c:1047
 do_coredump fs/coredump.c:1126 [inline]
 vfs_coredump+0x2762/0x3270 fs/coredump.c:1195
 get_signal+0xd33/0xf10 kernel/signal.c:3097
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
 irqentry_exit+0x14d/0x610 kernel/entry/common.c:165
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

read to 0xffff8881049adef0 of 8 bytes by task 4341 on cpu 1:
 generic_fillattr+0x283/0x340 fs/stat.c:106
 shmem_getattr+0x18b/0x210 mm/shmem.c:1315
 vfs_getattr_nosec+0x146/0x1e0 fs/stat.c:213
 vfs_getattr+0x48/0x60 fs/stat.c:262
 vfs_statx_path+0x28/0x140 fs/stat.c:299
 vfs_statx+0xc4/0x170 fs/stat.c:356
 vfs_fstatat+0x118/0x170 fs/stat.c:373
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat+0x55/0x3e0 fs/stat.c:532
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:532
 x64_sys_call+0xee6/0x2550 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000010f8 -> 0x0000000000001100

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4341 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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