From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f80.google.com (mail-ot1-f80.google.com [209.85.210.80]) (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 F233533AD9E for ; Fri, 30 Jan 2026 05:14:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769750077; cv=none; b=SIlLAdpg2o8WZTKgTDk1o2RrcnvwucSviyVlNuhrku8Phk4xKPAw/big1RFdTA5siMywZipGfMXREQUrCgHH8EEvQCmx+aR6gAgBX0erpe39ge8cW0aHJKG1MzYkQt5CGopmPUxOTkVfINSqr9GuvfPvl9+J7J8++WG0DcrDZ90= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769750077; c=relaxed/simple; bh=d7+T2RJO7nULQJuZtk2H2BMRMZ+2NKjSNlnNmZlE/EA=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=NhND8kUH6MXSqX92Uh7rxwQnIDVGlZWz/T3RoVZDAMZUnGmQfkzBz8PUfl/rUSELMc89QCk/Ue7HHj83A1sxu1pXts/ayMaRfEiiYiUQ+zW41msJ1Xt+eYe0dNEGK4ci1tAXe4n/rOVV0jLG+P9jp59nLoln94YoEVrgRsfgMjo= 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=209.85.210.80 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-ot1-f80.google.com with SMTP id 46e09a7af769-7d18e9ab16fso3882952a34.0 for ; Thu, 29 Jan 2026 21:14:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769750075; x=1770354875; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=WZBxNEkKoPRXPMzLcWsvsFY0BDmm7GFubz7Cg7pAEUM=; b=w1GttYESQNwsVkXIoD5/eVWYfcbRqWkHl/WER8taUN6rdNFB1AZJbs5jkFCYuPMpdG 5XF/a6znz6hp1iYONgiMZ9Lz9WXAkRtFKok3SSnJEA5/ukXkVURbAKuJ+FC/vorLHe4e 5qO5VxHdbOA8WMKdi9SBlbCSLsy3nEixyujkeAT1jrG8UVbEiSgyvHmnPjs0KVbfWagL +J3gIZKZuGNXUaW3MGE+vUza99d4c6r1dAxAy1J1zRhwXGT9aHbxFRJUoifEUdOZeXSY 9FOBpjeoEhdyKvoH7ZgH1KriikBsOhbIHoBY12SNPWO43OvjCbPxotSeykyMALF1AK+5 wIzg== X-Forwarded-Encrypted: i=1; AJvYcCVvOThE2YKpjC0c8cotpeR/rImwxzT8Mu721InFACfuFrt4LFVuZolp1rU0kaqmV8GIWSKZyZ4ExvsoKMg=@vger.kernel.org X-Gm-Message-State: AOJu0Yz1IPQCVFseUNQFzf664nRW3AleqBAKORISle28zk4UuG4v83Wu Th0YXELiT7md/V78ZXstmMP9uD14/YcrXwRUHMMp+FJ/AxgufxoeRGXHknlDEWh/fXNxgffJ81R beShplYiJCXDpEIwrtmFz+ndbu1ae8/QGGlQln/905y11lb9lXTYOpAD7ssE= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:ee0d:0:b0:662:c301:a278 with SMTP id 006d021491bc7-6630f358020mr725707eaf.45.1769750074944; Thu, 29 Jan 2026 21:14:34 -0800 (PST) Date: Thu, 29 Jan 2026 21:14:34 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <697c3e3a.a00a0220.35f26.000d.GAE@google.com> Subject: [syzbot] [iomap?] KASAN: use-after-free Write in iomap_write_end From: syzbot To: brauner@kernel.org, djwong@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 4d310797262f Merge tag 'pm-6.19-rc8' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17e91bfa580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4aae00ac5a9d2645 dashboard link: https://syzkaller.appspot.com/bug?extid=ea1cd4aa4d1e98458a55 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 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-4d310797.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/0731328b5303/vmlinux-4d310797.xz kernel image: https://storage.googleapis.com/syzbot-assets/fbeb5d7bc402/bzImage-4d310797.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ea1cd4aa4d1e98458a55@syzkaller.appspotmail.com loop0: detected capacity change from 0 to 32768 gfs2: fsid=syz:syz: Trying to join cluster "lock_nolock", "syz:syz" gfs2: fsid=syz:syz: Now mounting FS (format 1801)... gfs2: fsid=syz:syz.0: journal 0 mapped with 1 extents in 0ms gfs2: fsid=syz:syz.0: first mount done, others may mount overlay: ./bus is not a directory ================================================================== BUG: KASAN: use-after-free in iomap_write_end_inline fs/iomap/buffered-io.c:1032 [inline] BUG: KASAN: use-after-free in iomap_write_end+0x390/0x720 fs/iomap/buffered-io.c:1050 Write of size 1 at addr ffff88800e1d5904 by task syz.0.0/5322 CPU: 0 UID: 0 PID: 5322 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 mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106 iomap_write_end_inline fs/iomap/buffered-io.c:1032 [inline] iomap_write_end+0x390/0x720 fs/iomap/buffered-io.c:1050 iomap_write_iter fs/iomap/buffered-io.c:1123 [inline] iomap_file_buffered_write+0x52b/0xb30 fs/iomap/buffered-io.c:1189 gfs2_file_buffered_write+0x4eb/0x870 fs/gfs2/file.c:1061 gfs2_file_write_iter+0x976/0x1130 fs/gfs2/file.c:1166 iter_file_splice_write+0x99b/0x1100 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x101/0x160 fs/splice.c:1161 splice_direct_to_actor+0x53a/0xc70 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x195/0x290 fs/splice.c:1230 do_sendfile+0x535/0x7d0 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f224299aeb9 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:00007f2243773028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f2242c15fa0 RCX: 00007f224299aeb9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 00007f2242a08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 000000007ffff004 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2242c16038 R14: 00007f2242c15fa0 R15: 00007ffeffb7adf8 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x92c pfn:0xe1d5 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 ffffea0000387488 ffffea00008c1448 0000000000000000 raw: 000000000000092c 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 0x148c4a(GFP_NOFS|__GFP_HIGHMEM|__GFP_MOVABLE|__GFP_NOFAIL|__GFP_COMP|__GFP_HARDWALL), pid 5322, tgid 5321 (syz.0.0), ts 77159152107, free_ts 77205550804 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline] alloc_pages_noprof+0xa8/0x190 mm/mempolicy.c:2577 folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2587 filemap_alloc_folio_noprof+0x111/0x470 mm/filemap.c:1013 __filemap_get_folio_mpol+0x3fc/0xb00 mm/filemap.c:2006 __filemap_get_folio include/linux/pagemap.h:774 [inline] gfs2_getbuf+0x186/0x6d0 fs/gfs2/meta_io.c:144 gfs2_meta_read+0x109/0x8d0 fs/gfs2/meta_io.c:271 gfs2_meta_buffer+0x10f/0x2e0 fs/gfs2/meta_io.c:495 gfs2_meta_inode_buffer fs/gfs2/meta_io.h:70 [inline] __gfs2_iomap_get+0x193/0x1840 fs/gfs2/bmap.c:861 gfs2_iomap_begin+0x219/0x11e0 fs/gfs2/bmap.c:1109 iomap_iter+0x600/0xf30 fs/iomap/iter.c:110 __iomap_dio_rw+0xcc4/0x1e10 fs/iomap/direct-io.c:752 iomap_dio_rw+0x45/0xb0 fs/iomap/direct-io.c:847 page last free pid 74 tgid 74 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] free_unref_folios+0xdce/0x1510 mm/page_alloc.c:3030 shrink_folio_list+0x4930/0x5160 mm/vmscan.c:1603 evict_folios+0x4795/0x5880 mm/vmscan.c:4711 try_to_shrink_lruvec+0x88b/0xb20 mm/vmscan.c:4874 shrink_one+0x25c/0x710 mm/vmscan.c:4919 shrink_many mm/vmscan.c:4982 [inline] lru_gen_shrink_node mm/vmscan.c:5060 [inline] shrink_node+0x2f8b/0x35f0 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6901 [inline] balance_pgdat mm/vmscan.c:7084 [inline] kswapd+0x144c/0x2800 mm/vmscan.c:7354 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff88800e1d5800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88800e1d5880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88800e1d5900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88800e1d5980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88800e1d5a00: 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