[moderation] [fs?] KCSAN: data-race in generic_fillattr / inode_add_bytes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 34afb82a3c67 Merge tag '6.10-rc6-smb3-server-fixes' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15985041980000
kernel config: https://syzkaller.appspot.com/x/.config?x=d41a21b8562873d8
dashboard link: https://syzkaller.appspot.com/bug?extid=a088f9d6bf95dc66a923
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ja...@suse.com linux-...@vger.kernel.org linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4b686da2bc84/disk-34afb82a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ab076324e14e/vmlinux-34afb82a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/aa0de102d675/bzImage-34afb82a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a088f9...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in generic_fillattr / inode_add_bytes

read-write to 0xffff888113c40cd0 of 8 bytes by task 7488 on cpu 1:
__inode_add_bytes fs/stat.c:805 [inline]
inode_add_bytes+0x45/0xd0 fs/stat.c:818
__dquot_alloc_space+0x181/0x8a0 fs/quota/dquot.c:1695
dquot_alloc_space_nodirty include/linux/quotaops.h:299 [inline]
dquot_alloc_block_nodirty include/linux/quotaops.h:326 [inline]
shmem_inode_acct_blocks+0x124/0x230 mm/shmem.c:225
shmem_alloc_and_add_folio mm/shmem.c:1693 [inline]
shmem_get_folio_gfp+0x5d3/0xb70 mm/shmem.c:2055
shmem_get_folio mm/shmem.c:2160 [inline]
shmem_write_begin+0xa0/0x1c0 mm/shmem.c:2743
generic_perform_write+0x1d5/0x410 mm/filemap.c:4015
shmem_file_write_iter+0xc8/0xf0 mm/shmem.c:2919
__kernel_write_iter+0x24f/0x4e0 fs/read_write.c:523
dump_emit_page fs/coredump.c:893 [inline]
dump_user_range+0x3a7/0x550 fs/coredump.c:954
elf_core_dump+0x1aeb/0x1c30 fs/binfmt_elf.c:2083
do_coredump+0xff6/0x1860 fs/coredump.c:767
get_signal+0xdc1/0x1080 kernel/signal.c:2894
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
irqentry_exit_to_user_mode+0x94/0x130 kernel/entry/common.c:231
irqentry_exit+0x12/0x50 kernel/entry/common.c:334
exc_general_protection+0x33d/0x4d0 arch/x86/kernel/traps.c:644
asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:617

read to 0xffff888113c40cd0 of 8 bytes by task 3080 on cpu 0:
generic_fillattr+0x233/0x2f0 fs/stat.c:64
shmem_getattr+0x17b/0x200 mm/shmem.c:1139
vfs_getattr_nosec fs/stat.c:135 [inline]
vfs_getattr+0x19b/0x1e0 fs/stat.c:176
vfs_statx+0x140/0x320 fs/stat.c:248
vfs_fstatat+0xcd/0x100 fs/stat.c:304
__do_sys_newfstatat fs/stat.c:468 [inline]
__se_sys_newfstatat+0x58/0x260 fs/stat.c:462
__x64_sys_newfstatat+0x55/0x70 fs/stat.c:462
x64_sys_call+0x1451/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:263
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: 0x0000000000000ad0 -> 0x0000000000000ae8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3080 Comm: syz-executor Not tainted 6.10.0-rc7-syzkaller-00012-g34afb82a3c67 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================


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