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Fri, 19 Jun 2026 15:36:29 -0700 (PDT) Date: Fri, 19 Jun 2026 15:36:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a35c46d.951a15ca.164930.0003.GAE@google.com> Subject: [syzbot] [mm?] KCSAN: data-race in __percpu_counter_limited_add / percpu_counter_add_batch (3) From: syzbot To: akpm@linux-foundation.org, baolin.wang@linux.alibaba.com, hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 4A25F40003 X-Stat-Signature: 9a19bf4g5a6zzwcuexfwp6d7soh7upug X-HE-Tag: 1781908590-845585 X-HE-Meta: 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 BSIH5OIf 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 6S2+7yCK GnKUoxm7yRZ9+dvtbkUteHvJBkeZ+B2P/UAAnzBoKEFC2jYDLMBAQ5/5K3m/jk+zuiQqpA8+GbHWtrUT9F7P2kDvky7dqUO/IEcU1VcOU45d5INkiN9UU4br7LPAlQZ28rZmEU9s2U0/4gI1xWqwSHcb12pDkYGfrX8j7Ys6hs1Z7X3ma5QnfOSUMckPEwl76b+OVlzRRIFgafx4FZSpuBem3MB0Bh/BPLsg0zwmpCzVLSbi39Mbli+b7+2OU1kuKBL5X971YptVvsjDGO7MAytTCw7pp4YxHzlgFpPUTzmhPWoA5OKGzS2AfKj0hbvzKzCnZI9mA2E7PWpbRD6iqMFTzZwRTL4hsbCrjczKDbJdyubaqNHWrzqs3Lu6yIsvSvYCuU0h4PRlmScchUc290CB72pwf6RdX5f44qmc+kwffeWuAKoisVRx0moybLapKhidwOt8RN8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello, syzbot found the following issue on: HEAD commit: 5e2e14749c3d Merge tag 'landlock-7.2-rc1' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=115453b6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b0ae27ce66b92956 dashboard link: https://syzkaller.appspot.com/bug?extid=a3c71b9db9c11c270f59 compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a565c60a4762/disk-5e2e1474.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e593a6eb0057/vmlinux-5e2e1474.xz kernel image: https://storage.googleapis.com/syzbot-assets/d24b55020ea3/bzImage-5e2e1474.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a3c71b9db9c11c270f59@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in __percpu_counter_limited_add / percpu_counter_add_batch read-write to 0xffff88812a80e9d0 of 8 bytes by task 11484 on cpu 0: percpu_counter_add_batch+0x101/0x120 lib/percpu_counter.c:107 percpu_counter_add include/linux/percpu_counter.h:71 [inline] percpu_counter_sub include/linux/percpu_counter.h:277 [inline] shmem_inode_unacct_blocks mm/shmem.c:263 [inline] shmem_recalc_inode+0x143/0x1f0 mm/shmem.c:466 shmem_undo_range+0xb20/0xb60 mm/shmem.c:1272 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x132/0x520 mm/shmem.c:1407 evict+0x2a5/0x510 fs/inode.c:828 iput_final fs/inode.c:2022 [inline] iput+0x430/0x5a0 fs/inode.c:2071 filename_unlinkat+0x21f/0x410 fs/namei.c:5585 __do_sys_unlink fs/namei.c:5616 [inline] __se_sys_unlink+0x2b/0xe0 fs/namei.c:5613 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5613 x64_sys_call+0x2eb6/0x3020 arch/x86/include/generated/asm/syscalls_64.h:88 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88812a80e9d0 of 8 bytes by task 16836 on cpu 1: __percpu_counter_limited_add+0xc4/0x3f0 lib/percpu_counter.c:-1 percpu_counter_limited_add include/linux/percpu_counter.h:77 [inline] shmem_inode_acct_blocks+0xf4/0x230 mm/shmem.c:232 shmem_alloc_and_add_folio mm/shmem.c:1979 [inline] shmem_get_folio_gfp+0x5d3/0xd90 mm/shmem.c:2502 shmem_get_folio mm/shmem.c:2608 [inline] shmem_write_begin+0xfc/0x1f0 mm/shmem.c:3239 generic_perform_write+0x186/0x490 mm/filemap.c:4363 shmem_file_write_iter+0xc5/0xf0 mm/shmem.c:3414 __kernel_write_iter+0x30f/0x590 fs/read_write.c:621 dump_emit_page fs/coredump.c:1298 [inline] dump_user_range+0xa73/0xd00 fs/coredump.c:1372 elf_core_dump+0x21c0/0x2340 fs/binfmt_elf.c:2109 coredump_write+0xaf9/0xdd0 fs/coredump.c:1052 do_coredump fs/coredump.c:1131 [inline] vfs_coredump+0x2770/0x3290 fs/coredump.c:1200 get_signal+0xd33/0xf10 kernel/signal.c:3023 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 value changed: 0x000000000000459f -> 0x00000000000035b4 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 16836 Comm: syz.5.4499 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup