From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.167.197 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793557530; b=tU2rHh4aF86+ajC25994xPKPiOkuhl5v0f+roqDis+Z9nrMMUuesUGD6bKx/wsUkTn6F sHH9Vis9bk3y877M+GonOCrTh7CfWK8fbL5Fn0oty5GswW5MJFRakqv8a1Yt3oTBO5SAY jLru8tGSaNILjAku6naE9ImMfZDOlrFd1i2bL1Zuqp7kx09wuq1k1TVU8sVWcvnIGs7Tx NtIf35rKwxSIvE8wjTaOqxiyCePALYV0zkX23wckrfRfD6iwOTHJ6Hywj9nWntqgHMaRa R9zA6fuc2+6uQ/Gr1qSwXczTW9ui103RjhYrssBNUjF4ZJaLWIntsyyyKZmluLvsyhQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793557530; h=DMARC-Filter:Received:X-Google-DKIM-Signature:X-Gm-Message-State: MIME-Version:X-Received:Date:X-Google-Appengine-App-Id: X-Google-Appengine-App-Id-Alias:Message-ID:Subject:From:To: Content-Type; bh=CMF+rDxX3I6Jh93CcarKiFP3ZLIidiAmOkST9zJjDqc=; b=FjbtsWbYkgSGxTzfEX+OnQ0ZX+ZBsqN3cK7gxzRTxsHmdMAgyrz6vsNfsaIMz4KSfSn1 XNRSWw4Y/NX/BJCkt+7aryV7VQhYEhWsFaqwiIpUzP9woFVfQs/a5JFkx4vx3vpdS8t5b I1tkh7DkGds2cdIyrxsEbc96zs0pUeajtsN9cCMRZK5wyKAHF6le9/AkpO8smTHz6tkXx Jj2zApcKq2rPNn3l4XdREGO97csqTWghw2ZcjRyUXWX2mMCMUrAu/JKsWlILCOYTczFQI OPmaME2wT3gKcjS+pNok9yZgkxUZV6H/06hwll75T8qn5vVOvvG1O52GW6+bDC0AriA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.remote-ip=209.85.167.197 Received: from mail-oi1-f197.google.com (mail-oi1-f197.google.com [209.85.167.197]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6517C606A339 for ; Sun, 1 Nov 2026 18:25:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 6517C606A339 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi1-f197.google.com with SMTP id 5614622812f47-4e778acdbc6so4011197b6e.3 for ; Sun, 01 Nov 2026 10:25:30 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793557529; x=1794162329; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=CMF+rDxX3I6Jh93CcarKiFP3ZLIidiAmOkST9zJjDqc=; b=wKN3lr50nEIcItJnmx4X7M2uk0J+LRAgRZa9BYOMLzk8g/qcZ+1lskRIuDJC/f5PBl GTXsM1E5OJBAlTD9md+vFl2rE5H6AjhPgfboQKHfI/N0R6hyFaAzZR9kl2hNMCghdY75 Ehutnc8M52985N1kkCK9rneZe8fy8vzwJhgLqUzyjVnFuVhRIHvkllqnAa7fYkkEkbSN /0ubm3SbAJoRKpZxNaD3HKen53VGmoZfEi4NGo7jOL3bWp7pKO2U7TCUDaDJ+0QcIXqo d4/oOyxO8bXC43zTZjL96nP+mWaN2Nx8jjQY1z2PSJFwpw4HKW1+DgHANfeEIMXXnMVY T5Nw== X-Gm-Message-State: AFq9FYIdLZBnTZc3OmzWcDl4lSNH0KhbpBjiR6rKCOm6QCzzjcEP/k2w TWR+1PilsTwBIsEUZOVdclRVbRHtXD+uO7glm+O4AUoOgtr/ayLG44oEMLvDOX0DXl/N3A+khie E4z+oZ1gP7qpqz2OlMzidUGbiEWx/b8AxFQ6x3IBOBJLsWnAVXEFgMbdKAJQ= X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-Received: by 2002:a05:6808:1244:b0:510:7dc8:5ff7 with SMTP id 5614622812f47-5640deea651mr5941698b6e.19.1793557529004; Sun, 01 Nov 2026 10:25:29 -0800 (PST) Date: Sun, 01 Nov 2026 10:25:28 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ae78418.6552420f.2a0efc.005c.GAE@google.com> Subject: [syzbot] [mm?] general protection fault in validate_mm (2) From: syzbot To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 36aad21d50d1 Merge tag 'ksmbd-for-7.4-rc1-part2' of git://.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=12b81cb1580000 kernel config: https://syzkaller.appspot.com/x/.config?x=bd712e5dbce1d1a0 dashboard link: https://syzkaller.appspot.com/bug?extid=10e72ea5747737bcd2ad compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 userspace arch: i386 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12a58f95580000 AI-generated root cause summary: In validate_mm() (mm/vma.c), struct anon_vma *anon_vma = vma->anon_vma caches the anon_vma pointer at the beginning of the VMA iteration loop. In vms_complete_munmap_vmas(), mm->mmap_lock is downgraded to a read lock before validate_mm() is called, allowing a concurrent page fault on another thread to populate vma->anon_vma via __anon_vma_prepare(). When this race occurs, vma_has_anon_rmap(vma) evaluates to true by re-reading vma->anon_vma, but anon_vma_lock_read(anon_vma) is invoked with the stale NULL local variable, resulting in an unhandled NULL-pointer dereference and kernel crash. full analysis: https://syzkaller.appspot.com/x/ai_root_cause?x=10e72ea5747737bcd2ad IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+10e72ea5747737bcd2ad@syzkaller.appspotmail.com Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 6142 Comm: syz-executor263 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:anon_vma_lock_read mm/internal.h:315 [inline] RIP: 0010:validate_mm+0x3d4/0x780 mm/vma.c:707 Code: d2 e0 98 ff 48 89 df e8 5a 10 f1 ff c6 05 db a8 dd 0f 01 90 0f 0b 90 e9 04 fd ff ff e8 b5 e0 98 ff 48 8b 44 24 08 48 c1 e8 03 <80> 3c 28 00 0f 85 25 03 00 00 48 8b 44 24 08 4c 8d 63 30 48 8b 00 RSP: 0018:ffffc900040d7870 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88806b186000 RCX: 0000000000000000 RDX: ffff888000794b00 RSI: ffffffff8274c56b RDI: 0000000000000005 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffff88806b186083 R11: 0000000000000001 R12: ffff88806b186010 R13: ffff88806b186040 R14: 0000000000000001 R15: 000000000000003d FS: 0000000000000000(0000) GS:ffff888095281000(0063) knlGS:000000005727b3c0 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000f7f72000 CR3: 000000004e463000 CR4: 0000000000352ef0 Call Trace: vms_complete_munmap_vmas+0x83b/0xdf0 mm/vma.c:1437 do_vmi_align_munmap+0x44f/0x5f0 mm/vma.c:1677 do_vmi_munmap+0x1f8/0x410 mm/vma.c:1725 __vm_munmap+0x196/0x3c0 mm/vma.c:3562 __do_sys_munmap mm/mmap.c:1094 [inline] __se_sys_munmap mm/mmap.c:1091 [inline] __ia32_sys_munmap+0x57/0x80 mm/mmap.c:1091 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] __do_fast_syscall_32+0x14b/0x8c0 arch/x86/entry/syscall_32.c:282 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:307 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7eaafbc Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8 RSP: 002b:00000000ff8ab10c EFLAGS: 00000296 ORIG_RAX: 000000000000005b RAX: ffffffffffffffda RBX: 0000000020088000 RCX: 0000000000001000 RDX: 00000000f7f70ff4 RSI: 00000000000000fb RDI: 0000000000000040 RBP: 00000000ff8ab168 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:anon_vma_lock_read mm/internal.h:315 [inline] RIP: 0010:validate_mm+0x3d4/0x780 mm/vma.c:707 Code: d2 e0 98 ff 48 89 df e8 5a 10 f1 ff c6 05 db a8 dd 0f 01 90 0f 0b 90 e9 04 fd ff ff e8 b5 e0 98 ff 48 8b 44 24 08 48 c1 e8 03 <80> 3c 28 00 0f 85 25 03 00 00 48 8b 44 24 08 4c 8d 63 30 48 8b 00 RSP: 0018:ffffc900040d7870 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88806b186000 RCX: 0000000000000000 RDX: ffff888000794b00 RSI: ffffffff8274c56b RDI: 0000000000000005 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffff88806b186083 R11: 0000000000000001 R12: ffff88806b186010 R13: ffff88806b186040 R14: 0000000000000001 R15: 000000000000003d FS: 0000000000000000(0000) GS:ffff888095281000(0063) knlGS:000000005727b3c0 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000f7f72000 CR3: 000000004e463000 CR4: 0000000000352ef0 ---------------- Code disassembly (best guess), 4 bytes skipped: 0: 48 89 df mov %rbx,%rdi 3: e8 5a 10 f1 ff call 0xfff11062 8: c6 05 db a8 dd 0f 01 movb $0x1,0xfdda8db(%rip) # 0xfdda8ea f: 90 nop 10: 0f 0b ud2 12: 90 nop 13: e9 04 fd ff ff jmp 0xfffffd1c 18: e8 b5 e0 98 ff call 0xff98e0d2 1d: 48 8b 44 24 08 mov 0x8(%rsp),%rax 22: 48 c1 e8 03 shr $0x3,%rax * 26: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction 2a: 0f 85 25 03 00 00 jne 0x355 30: 48 8b 44 24 08 mov 0x8(%rsp),%rax 35: 4c 8d 63 30 lea 0x30(%rbx),%r12 39: 48 8b 00 mov (%rax),%rax --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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