From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EE8926E71F; Mon, 19 Jan 2026 06:36:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768804617; cv=none; b=iPlUofWKmwVkoI67sLu5ObW+707Spzp61PKduqoymDRRmcm216EqvzHHdArYOKj76tMPHTycfGBF2UjGMzUR8XFE4B08m6/R0EBNU2JD/XQY7fYUiv4jZZYT7rtuOAn6W2VnRcG/ZTabXGDmbvXiY1yLt+XpL6V/ZoZEKr85cEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768804617; c=relaxed/simple; bh=r0Y7Jyr5JGyXXTDiyp/H8tlBTszB9xd77VfWFqsjq0g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Uc6ArIHyceriAXZ97wHbDy9HtqyVLWPu24K6qjHclFb1p/XIn35hu/LnmucxboAI6IU0lX944dWfvk0hZCLi/KqRh6AVaoRAyH35hcnyh2qBGYxGzqQ08cJaF4lY4pr+9FippBjkPLCpX/vtWBw7Jk+bjH45a4GHiwJZ9daY2xo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=VgmbmRwy; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="VgmbmRwy" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ARhYh0qWKr7ukcVDai4Q/eUenpvB3MxH8FzufR+J1dU=; b=VgmbmRwyYaqg9E5PpLmHtW+VOZ NiSPFrKnpb/4eFjCBlcRcV3DkTWEFqPH7pjVEr5QPQ3QRRhfBnrXpNfx/awZHsOvy57USIPGp1T7W F5hKKk16pGaMQBoRX9KeWXlTFPO7Dn8KfecnNO58iypfz8819QY2iI4SvlvKw0SVVUeqSnk03YO5D UlhGw4eTTT/v/ZFqVlLxZbLQAZa9kPGRLz/rvNLGpRlS73S/L9ZYflrqSn5ZpkMG4Z4CvY62p6Jd1 CBvu3HA/CkCSXrgq/GhpE7keuqfx/x4fqrTBHRHQmNibKuCr/TZnS8n1PDmacQXnqA3ns6nbWOUNH cEOCLdOA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vhisg-00000001POg-0AqA; Mon, 19 Jan 2026 06:36:54 +0000 Date: Sun, 18 Jan 2026 22:36:54 -0800 From: Christoph Hellwig To: syzbot Cc: cem@kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, mikulas@artax.karlin.mff.cuni.cz, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [xfs?] KASAN: use-after-free Read in hpfs_bplus_lookup Message-ID: References: <696aa7da.a70a0220.31956c.001a.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <696aa7da.a70a0220.31956c.001a.GAE@google.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Any idea why this Ccs the xfs list? On Fri, Jan 16, 2026 at 01:04:26PM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: b71e635feefc Merge tag 'cgroup-for-6.19-rc5-fixes' of git:.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=10efa99a580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=7b058fb1d7dbe6b1 > dashboard link: https://syzkaller.appspot.com/bug?extid=8debf4b3f7c7391cd8eb > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10cd15fa580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=152a4052580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/40abbbbc34a8/disk-b71e635f.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/74edfb8073f7/vmlinux-b71e635f.xz > kernel image: https://storage.googleapis.com/syzbot-assets/3b5198043bfa/bzImage-b71e635f.xz > mounted in repro #1: https://storage.googleapis.com/syzbot-assets/7f1692afbc9c/mount_0.gz > fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1609599a580000) > mounted in repro #2: https://storage.googleapis.com/syzbot-assets/d09b0f5dc58e/mount_2.gz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8debf4b3f7c7391cd8eb@syzkaller.appspotmail.com > > hpfs: filesystem error: invalid number of hotfixes: 2066844986, used: 2066844985; already mounted read-only > hpfs: filesystem error: improperly stopped > hpfs: filesystem error: warning: spare dnodes used, try chkdsk > hpfs: You really don't want any checks? You are crazy... > hpfs: hpfs_map_sector(): read error > hpfs: code page support is disabled > hpfs: filesystem error: map_dirent: not a directory > hpfs: hpfs_map_4sectors(): unaligned read > hpfs: filesystem error: unable to find root dir > ================================================================== > BUG: KASAN: use-after-free in hpfs_bplus_lookup+0x4dc/0x860 fs/hpfs/anode.c:38 > Read of size 4 at addr ffff888052abe004 by task syz.0.27/6198 > > CPU: 1 UID: 0 PID: 6198 Comm: syz.0.27 Not tainted syzkaller #0 PREEMPT_{RT,(full)} > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 > Call Trace: > > dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 > print_address_description mm/kasan/report.c:378 [inline] > print_report+0xca/0x240 mm/kasan/report.c:482 > kasan_report+0x118/0x150 mm/kasan/report.c:595 > hpfs_bplus_lookup+0x4dc/0x860 fs/hpfs/anode.c:38 > hpfs_bmap+0x22a/0x4d0 fs/hpfs/file.c:54 > hpfs_get_block+0xa8/0x6e0 fs/hpfs/file.c:87 > do_mpage_readpage+0x822/0x1990 fs/mpage.c:222 > mpage_readahead+0x3b0/0x790 fs/mpage.c:371 > read_pages+0x17a/0x580 mm/readahead.c:163 > page_cache_ra_unbounded+0x68b/0x8c0 mm/readahead.c:302 > filemap_get_pages+0x446/0x1ee0 mm/filemap.c:2690 > filemap_read+0x3f9/0x11a0 mm/filemap.c:2800 > __kernel_read+0x4d8/0x970 fs/read_write.c:530 > integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28 > ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:480 [inline] > ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline] > ima_calc_file_hash+0x86a/0x1700 security/integrity/ima/ima_crypto.c:568 > ima_collect_measurement+0x42e/0x900 security/integrity/ima/ima_api.c:293 > process_measurement+0x112a/0x1a80 security/integrity/ima/ima_main.c:406 > ima_file_check+0xd9/0x130 security/integrity/ima/ima_main.c:663 > security_file_post_open+0xbb/0x290 security/security.c:2652 > do_open fs/namei.c:4639 [inline] > path_openat+0x3472/0x3df0 fs/namei.c:4796 > do_filp_open+0x1fa/0x410 fs/namei.c:4823 > do_sys_openat2+0x121/0x200 fs/open.c:1430 > do_sys_open fs/open.c:1436 [inline] > __do_sys_openat fs/open.c:1452 [inline] > __se_sys_openat fs/open.c:1447 [inline] > __x64_sys_openat+0x138/0x170 fs/open.c:1447 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fb59539f749 > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fff3ac53cb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 > RAX: ffffffffffffffda RBX: 00007fb5955f5fa0 RCX: 00007fb59539f749 > RDX: 0000000000000000 RSI: 0000200000004280 RDI: ffffffffffffff9c > RBP: 00007fb595423f91 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 00007fb5955f5fa0 R14: 00007fb5955f5fa0 R15: 0000000000000004 > > > The buggy address belongs to the physical page: > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7fb58c615 pfn:0x52abe > flags: 0x80000000000000(node=0|zone=1) > raw: 0080000000000000 ffffea00014aafc8 ffff8880b8842d30 0000000000000000 > raw: 00000007fb58c615 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 6198, tgid 6198 (syz.0.27), ts 130045840131, free_ts 130049000115 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857 > prep_new_page mm/page_alloc.c:1865 [inline] > get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915 > __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 > alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 > folio_alloc_mpol_noprof mm/mempolicy.c:2505 [inline] > vma_alloc_folio_noprof+0xe4/0x280 mm/mempolicy.c:2540 > folio_prealloc+0x30/0x180 mm/memory.c:-1 > alloc_anon_folio mm/memory.c:5165 [inline] > do_anonymous_page mm/memory.c:5222 [inline] > do_pte_missing+0x86a/0x27a0 mm/memory.c:4399 > handle_pte_fault mm/memory.c:6273 [inline] > __handle_mm_fault mm/memory.c:6411 [inline] > handle_mm_fault+0xcc1/0x1330 mm/memory.c:6580 > do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 > handle_page_fault arch/x86/mm/fault.c:1476 [inline] > exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532 > asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 > page last free pid 6198 tgid 6198 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1406 [inline] > free_unref_folios+0xc28/0x1810 mm/page_alloc.c:3000 > folios_put_refs+0x569/0x670 mm/swap.c:1002 > free_pages_and_swap_cache+0x4be/0x520 mm/swap_state.c:358 > __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline] > tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] > tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] > tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404 > tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 > vms_clear_ptes+0x42b/0x530 mm/vma.c:1238 > vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1280 > do_vmi_align_munmap+0x372/0x450 mm/vma.c:1539 > do_vmi_munmap+0x253/0x2e0 mm/vma.c:1587 > __vm_munmap+0x207/0x380 mm/vma.c:3203 > __do_sys_munmap mm/mmap.c:1077 [inline] > __se_sys_munmap mm/mmap.c:1074 [inline] > __x64_sys_munmap+0x60/0x70 mm/mmap.c:1074 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Memory state around the buggy address: > ffff888052abdf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff888052abdf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >ffff888052abe000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > ^ > ffff888052abe080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > ffff888052abe100: 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 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 > ---end quoted text---