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Wed, 18 Feb 2026 13:59:31 -0800 (PST) Date: Wed, 18 Feb 2026 13:59:31 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69963643.a70a0220.2c38d7.0120.GAE@google.com> Subject: [syzbot] [mm?] kernel BUG in __page_table_check_zero (3) From: syzbot To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pasha.tatashin@soleen.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 7655C40012 X-Stat-Signature: kwze91hisk5u8oy1dgcb6tcmy9aud451 X-HE-Tag: 1771451972-718637 X-HE-Meta: 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 4NL3RdLR 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 0s+GcE7B 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 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: 18be4ca5cb4e riscv: lib: optimize strlen loop efficiency git tree: git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git for-next console output: https://syzkaller.appspot.com/x/log.txt?x=10c59b3a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=781a4eb07921464d dashboard link: https://syzkaller.appspot.com/bug?extid=2b5fe617654be3d8848b compiler: riscv64-linux-gnu-gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 userspace arch: riscv64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/a741b348759c/non_bootable_disk-18be4ca5.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c6b87a8d77c4/vmlinux-18be4ca5.xz kernel image: https://storage.googleapis.com/syzbot-assets/d5126373321c/Image-18be4ca5.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2b5fe617654be3d8848b@syzkaller.appspotmail.com ------------[ cut here ]------------ kernel BUG at [] mm/page_table_check.c:142! Kernel BUG [#1] Modules linked in: CPU: 0 UID: 0 PID: 3940 Comm: syz.1.16 Not tainted syzkaller #0 PREEMPT Hardware name: riscv-virtio,qemu (DT) epc : __page_table_check_zero+0x396/0x544 mm/page_table_check.c:142 ra : __page_table_check_zero+0x396/0x544 mm/page_table_check.c:142 epc : ffffffff80bfdcce ra : ffffffff80bfdcce sp : ffff8f800af273e0 gp : ffffffff89f9df20 tp : ffffaf8013f64f80 t0 : ffff8f800af27380 t1 : fffff5ef0269a409 t2 : 0000000000000000 s0 : ffff8f800af27450 s1 : ffffaf80134d2048 a0 : 0000000000000005 a1 : 0000000000000000 a2 : 0000000000000002 a3 : ffffffff80bfdcce a4 : 0000000000000000 a5 : ffffaf8013f65f80 a6 : 0000000000000003 a7 : ffffaf80134d204b s2 : 0000000000000001 s3 : 0000000000000000 s4 : ffffaf80134d2000 s5 : dfffffff00000000 s6 : 00000000000b2a00 s7 : 0000000000000200 s8 : 0000000000000009 s9 : 0000000000007fff s10: fffffffef1416bb0 s11: ffffffff8a0b5d80 t3 : 0000000000000001 t4 : fffff5ef0269a409 t5 : fffff5ef0269a40a t6 : 0000000000000002 ssp : 0000000000000000 status: 0000000200000120 badaddr: ffffffff80bfdcce cause: 0000000000000003 [] __page_table_check_zero+0x396/0x544 mm/page_table_check.c:142 [] page_table_check_free include/linux/page_table_check.h:43 [inline] [] free_pages_prepare mm/page_alloc.c:1434 [inline] [] free_unref_folios+0xa22/0x1dc8 mm/page_alloc.c:3030 [] folios_put_refs+0x41c/0x61c mm/swap.c:1002 [] free_pages_and_swap_cache+0x29c/0x480 mm/swap_state.c:358 [] __tlb_batch_free_encoded_pages+0xe4/0x25c mm/mmu_gather.c:137 [] tlb_batch_pages_flush mm/mmu_gather.c:150 [inline] [] tlb_flush_mmu_free mm/mmu_gather.c:398 [inline] [] tlb_flush_mmu mm/mmu_gather.c:405 [inline] [] tlb_finish_mmu+0x188/0x824 mm/mmu_gather.c:530 [] exit_mmap+0x396/0xca8 mm/mmap.c:1290 [] __mmput+0x106/0x3d0 kernel/fork.c:1173 [] mmput+0x74/0x88 kernel/fork.c:1196 [] exit_mm kernel/exit.c:581 [inline] [] do_exit+0x792/0x2828 kernel/exit.c:959 [] __do_sys_exit kernel/exit.c:1079 [inline] [] __se_sys_exit kernel/exit.c:1077 [inline] [] __riscv_sys_exit+0x48/0x54 kernel/exit.c:1077 [] syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 [] do_trap_ecall_u+0x3d2/0x58c arch/riscv/kernel/traps.c:344 [] handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 Code: 7f80 8526 c0ef ec3f 8a2a b791 6097 ff90 80e7 7e60 (9002) 6097 ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 7f80 flw fs0,56(a5) 2: 8526 mv a0,s1 4: ec3fc0ef jal 0xffffffffffffcec6 8: 8a2a mv s4,a0 a: b791 j 0xffffffffffffff4e c: ff906097 auipc ra,0xff906 10: 7e6080e7 jalr 2022(ra) # 0xff9067f2 * 14: 9002 ebreak <-- trapping instruction 16: 9760 .short 0x6097 --- 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