From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f79.google.com (mail-oo1-f79.google.com [209.85.161.79]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D5AABEEBA for ; Thu, 9 Jul 2026 00:07:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783555648; cv=none; b=chKBU8BmSIEvJ8oqSvqyBy0pLGUsEeJ2dxBCQ1Yr5f0y1A9y5o4b6DyCLWHXmyerEVY7JrvGrMwQckYvUtJJSeC7LULT3vPirNh/9cDu0Kk5+HprEqjaJRUfBgbhNbXxA9OETx4/Y2WOw7Sf6nFZEUggArqgX1aAU7ht48vyHCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783555648; c=relaxed/simple; bh=G26upqMPQ8wCLsQGyEc/DIBHSMGL4tSOOyVHGvaz9W0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=NyQs/+3+OOC/t1WcAEnCsetj9lB6s+PwE7v68TCvRwmsdo2syU+/fwVBeTli6f8KqE05XcpEQ1NRJq7FYGlKpyXm5KfS/mlZ0/GhNRSp6VTNTefYH9NS0otBYVDNP1LtrFUvZ9mjNWSbzkNH/ECwEA8NJyBlKoFVOATYpJego/E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.79 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-oo1-f79.google.com with SMTP id 006d021491bc7-6a31c08023cso441774eaf.0 for ; Wed, 08 Jul 2026 17:07:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783555646; x=1784160446; 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=4tDgcBSVeZFyvqNSj3NPT1ZaqMIC8R3a3L88HwnQO0Y=; b=JF39f7+cVzObqN7Mm2/o9q9/rNtFABpdDOhu0aOsl7UqsgLx2jn1GKvsYbnTccDQuY BrZngdHEnI3FYDGUMv0605jrtCkU+axlci+coOyrTKmZi3KhBselZS7fVsGDt88IG1+Y 2RanuQwGodKeDCxoYnEWC1x6qZ1tdDCmu/XYhta5y/UkwY28ttWoIsstuURJ7xHDJNWm r0bj14vuFJOWFeg6+DbRGxGUQHlRUUMcPgXm1sfHN7uyjhmPlBZPJzQTsZdv797FVaY7 Tg6H8aoi/haNLkZFavyaIpNTzBSMnxQMfjdFxW2rGlpMciPevpCQfVIemnMeyTKZEiX0 1lAg== X-Forwarded-Encrypted: i=1; AFNElJ+Yh+crnj/ieCVz6MIGQLF6CDncWxGdIkel8XDpG/PYTQbTPTD6e+5HGKkLwrS4M1BXxRyP9iScVSHX50M=@vger.kernel.org X-Gm-Message-State: AOJu0YxEyJ6AzuiUUjotkJpmJQ2gWs3YHyPMwCgOlxDrYpsyyzMp0nS0 V7FABQaJZW/tlEkkorMPiChNDFoc0iHSzx811nTmJkBhck/xSqZ9aagJHo+94qS45mW7eFAHege SrleoAXbMQp9nJ5ZW/9wciXr07x/CMGdbsz75a33VKqnL2EBBbJ7BcE628es= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:a0e:b0:6a1:4507:3535 with SMTP id 006d021491bc7-6a37da3e071mr391672eaf.38.1783555645780; Wed, 08 Jul 2026 17:07:25 -0700 (PDT) Date: Wed, 08 Jul 2026 17:07:25 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a4ee63d.c76b52dc.34afef.0024.GAE@google.com> Subject: [syzbot] [ext4?] KASAN: use-after-free Read in ext4_search_dir (3) From: syzbot To: adilger.kernel@dilger.ca, jack@suse.cz, libaokun@linux.alibaba.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, ojaswin@linux.ibm.com, ritesh.list@gmail.com, syzkaller-bugs@googlegroups.com, tytso@mit.edu, yi.zhang@huawei.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: d2c9a99135da Merge tag 'device-id-rework' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=138fec6e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=20c9876b0f77b546 dashboard link: https://syzkaller.appspot.com/bug?extid=4eb78541a595c5ad659f compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-d2c9a991.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c8723eec7ee9/vmlinux-d2c9a991.xz kernel image: https://storage.googleapis.com/syzbot-assets/f5a482d9ade0/bzImage-d2c9a991.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4eb78541a595c5ad659f@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in ext4_search_dir+0x180/0x250 fs/ext4/namei.c:1469 Read of size 1 at addr ffff88801323b3aa by task syz.0.0/5323 CPU: 0 UID: 0 PID: 5323 Comm: syz.0.0 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 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 ext4_search_dir+0x180/0x250 fs/ext4/namei.c:1469 ext4_find_inline_entry+0x502/0x650 fs/ext4/inline.c:1639 __ext4_find_entry+0x315/0x1cd0 fs/ext4/namei.c:1542 ext4_lookup_entry fs/ext4/namei.c:1703 [inline] ext4_lookup+0x17b/0x710 fs/ext4/namei.c:1769 lookup_open fs/namei.c:4481 [inline] open_last_lookups fs/namei.c:4608 [inline] path_openat+0x111f/0x3830 fs/namei.c:4856 do_file_open+0x23e/0x4a0 fs/namei.c:4888 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_open fs/open.c:1382 [inline] __se_sys_open fs/open.c:1378 [inline] __x64_sys_open+0x11e/0x150 fs/open.c:1378 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdc5619de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdc56fc5fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fdc56426090 RCX: 00007fdc5619de59 RDX: 0000000000000000 RSI: 0000000000064842 RDI: 00002000000005c0 RBP: 00007fdc56233e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdc56426128 R14: 00007fdc56426090 R15: 00007ffea8722208 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xa96 pfn:0x1323b flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000a96 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 5322, tgid 5321 (syz.0.0), ts 105785277419, free_ts 105927156983 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_pages_mpol+0x212/0x380 mm/mempolicy.c:2490 folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2509 shmem_alloc_folio mm/shmem.c:1907 [inline] shmem_alloc_and_add_folio+0x43e/0xf60 mm/shmem.c:1949 shmem_get_folio_gfp+0x5da/0x16d0 mm/shmem.c:2502 shmem_get_folio mm/shmem.c:2608 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3239 generic_perform_write+0x2d5/0x8f0 mm/filemap.c:4358 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3414 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 69 tgid 69 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] free_unref_folios+0xd84/0x14a0 mm/page_alloc.c:3011 shrink_folio_list+0x2b7d/0x5330 mm/vmscan.c:1513 evict_folios+0x3821/0x4b40 mm/vmscan.c:4835 try_to_shrink_lruvec+0xb4f/0xed0 mm/vmscan.c:4983 shrink_one+0x233/0x730 mm/vmscan.c:5024 shrink_many mm/vmscan.c:5087 [inline] lru_gen_shrink_node mm/vmscan.c:5165 [inline] shrink_node+0x3303/0x3b60 mm/vmscan.c:6154 kswapd_shrink_node mm/vmscan.c:7008 [inline] balance_pgdat mm/vmscan.c:7186 [inline] kswapd+0x17b6/0x31c0 mm/vmscan.c:7462 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88801323b280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88801323b300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88801323b380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88801323b400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88801323b480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== --- 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