From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831574; b=ziW+LIviWgT78P7JxLzAQkGaOV6ofWJxNCLiXCGFXEUuIJWszAwXuDmqHU7j2bXPzolW zKQlsZOBOSXh8rq89r6P/sHq9cR23JQMTYg/6O2RM9loZlhuiKve4UJmFkF13DjwE3ng8 nOKpE9RT2cpz5IrqnmUfWc8BLm1XlqmtIV34MbLQxc2VW9hHBnvAnjUuUeo2y99fmThB8 q4yVQ711ORe0ZeOIbZqs7JNWKphTuqbG9DdsRrX517R0YBXat71y5ebALgbuT4iAXgoWw m9XMZZwpxM7GpfudeCccs8RldWum3bH0M/8WVs+dUFbik73REf/mP7TWxC+HeB73f4Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831574; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=o0aUCZtcNn3d25ZBrQkGE2vYCdRFTm5K9GOudYL+sao=; b=cTKN+F4ke6O4N+cjd927LNOltJhSSQsnEcYzweKKUn+yqavXKLN2gEJDKpk1BbQw7i7f tj6pW0vxF0zYcK1my2u2/KDOvjSQRitpTqu1H2i5oJJQ83R61dTdxJW26TFkKA8Geh8ls 3XqGwo3RarhueJ+jM79C5DeTyPwfKnYA+XIWPOinqDZUatutZvQRf7HLzmed7J741Eavp CB9m9ZT5R44QMBx+3xJxYX1Dlr8RLChMiw4mea6OWAL9LvS1Dz58tzAXT/UI/bWtg9zQs ndYEvXKUTAdarjeHN/A80HOGcePZXhaRdM/DIj8mqEavqiebPjcrxFsapcvNV4HXTqA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="r/HFqJpN"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 65FF6606AB0A; Wed, 4 Nov 2026 22:32:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=r/HFqJpN Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CC1A1F00A15; Wed, 4 Nov 2026 22:32:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831574; bh=o0aUCZtcNn3d25ZBrQkGE2vYCdRFTm5K9GOudYL+sao=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=r/HFqJpNhqt5ZCC14f0u66QaUQfVEcKbZB6e816n9zOyqrKceOyqybFCIUiGL1D3i KgmffuZAnqszQPf/zhWfVWbyYRB39g9WNVqnjzInJEPOQreFRh5hXX1wrGrGHyJK3+ /bR6YoEPSdzNMzovFCvGawmIhW+dDIy6znSKRTvI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cen Zhang , Andrew Morton , Joseph Qi , Mark Fasheh , Joel Becker , Heming Zhao , Jia-Ju Bai , jjzuming@gmail.com Subject: [PATCH 6.18 0758/1005] ocfs2: snapshot dentry names in file and setattr traces Date: Wed, 4 Nov 2026 16:08:11 -0500 Message-ID: <20261104211104.666571122@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang commit 8cd3ff30659775a6831c66687a69d2b83d163591 upstream. Patch series "ocfs2: stabilize dentry names in file and setattr traces", v4. Snapshot names at all six users of ocfs2__file_ops and at the separate setattr event. Patch 1 handles the five ordinary file-operation callers and setattr. Patch 2 handles release separately to preserve its locked open-count sample and take the snapshot outside that critical section. The release explanation distinguishes its existing RCU lifetime coverage from name/length consistency. It does not claim that the ordinary callers' external-name UAF interleaving crosses the held inode spinlock. The release source change is unchanged from v3. Patch 1 also removes the read callback's redundant NULL-inode check. The two patches apply independently and leave trace formats unchanged. This patch (of 2): The open, fsync, read, write and splice-read trace calls pass the live dentry name and length to the shared ocfs2__file_ops event class. ocfs2_setattr() passes the same unprotected arguments to its own event. Both events size and copy a __string field separately. A reference to the dentry does not pin the external storage backing an individual name. With an event enabled, a caller can be preempted after loading the name pointer. A long-to-short rename can then replace the name and reclaim its old external allocation before the trace callback sizes or copies it, provided no other snapshot retains that allocation. The setattr inode lock does not exclude every rename: a same-directory rename of a source directory need not take that directory's inode lock. It can therefore change the dentry name while setattr records its event. Inline names and separately loaded lengths can also change during trace record sizing and copying. Take a dentry name snapshot around each of these six trace calls and pass both the string and length from the snapshot. Check event enablement before taking a snapshot. Keep the event classes and formats unchanged. Also remove the redundant NULL-inode check in the read callback. file_inode() returns the open file's inode, which is already used by the trace call above the check. The historical report below is from the read path. KASAN report as below: BUG: KASAN: slab-use-after-free in strlen+0x85/0xa0 Read of size 1 at addr ffff88810a5b2b18 by task python3/496 [CPU and host details omitted.] Call Trace: dump_stack_lvl+0x93/0xd0 print_report+0xce/0x630 ? strlen+0x85/0xa0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x20e/0x420 ? strlen+0x85/0xa0 kasan_report+0xe0/0x110 ? strlen+0x85/0xa0 strlen+0x85/0xa0 trace_event_raw_event_ocfs2__file_ops+0xf0/0x480 ? __pfx_trace_event_raw_event_ocfs2__file_ops+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? pmbd_probe_hit_cookie+0xe7/0x1c0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_pmbd_probe_hit_cookie+0x10/0x10 ocfs2_file_read_iter+0x6cd/0xb30 ? __pfx_ocfs2_file_read_iter+0x10/0x10 ? selinux_file_permission+0x11d/0x540 ? srso_alias_return_thunk+0x5/0xfbef5 ? security_file_permission+0x26/0x80 vfs_read+0x7d2/0xc20 ? __pfx_vfs_read+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_do_sys_openat2+0x10/0x10 ksys_read+0x111/0x200 ? __pfx_ksys_read+0x10/0x10 ? irqentry_exit+0xbe/0x820 ? srso_alias_return_thunk+0x5/0xfbef5 ? trace_hardirqs_on_prepare+0x11d/0x150 ? srso_alias_return_thunk+0x5/0xfbef5 do_syscall_64+0x114/0x620 entry_SYSCALL_64_after_hwframe+0x77/0x7f [User register dump omitted.] Allocated by task 489: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kmalloc_noprof+0x2de/0x780 __d_alloc+0x5fc/0x8c0 d_alloc_parallel+0x106/0x11d0 lookup_open+0x3ff/0x13e0 path_openat+0x95e/0x2020 do_file_open+0x21e/0x470 do_sys_openat2+0xf4/0x1b0 __x64_sys_openat+0x136/0x1e0 do_syscall_64+0x114/0x620 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 0: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x5f/0x80 __rcu_free_sheaf_prepare+0x65/0x2a0 rcu_free_sheaf_nobarn+0x1d/0x50 rcu_core+0x6be/0x1ed0 handle_softirqs+0x1fa/0x8d0 __irq_exit_rcu+0x113/0x1e0 irq_exit_rcu+0xe/0x20 sysvec_apic_timer_interrupt+0x6c/0x80 asm_sysvec_apic_timer_interrupt+0x1a/0x20 The buggy address belongs to the object at ffff88810a5b2b00 which belongs to the cache kmalloc-rcl-192 of size 192 The buggy address is located 24 bytes inside of freed 192-byte region [ffff88810a5b2b00, ffff88810a5b2bc0) [Page and shadow-memory dumps omitted.] Link: https://lore.kernel.org/pm-ocfs2-objects-candidate-0088-v7-6324344256f0c3b1c3d8-0@gmail.com Link: https://lore.kernel.org/pm-ocfs2-objects-candidate-0088-v7-6324344256f0c3b1c3d8-1@gmail.com Fixes: 468eedde23d6 ("ocfs2: Remove mlog(0) from fs/ocfs2/file.c") Signed-off-by: Cen Zhang Signed-off-by: Andrew Morton Reviewed-by: Joseph Qi Assisted-by: LLM Cc: Mark Fasheh Cc: Joel Becker Cc: Heming Zhao Cc: Jia-Ju Bai Cc: Cc: Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/file.c | 102 +++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 65 insertions(+), 37 deletions(-) --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -84,10 +84,17 @@ static int ocfs2_file_open(struct inode int mode = file->f_flags; struct ocfs2_inode_info *oi = OCFS2_I(inode); - trace_ocfs2_file_open(inode, file, file->f_path.dentry, - (unsigned long long)oi->ip_blkno, - file->f_path.dentry->d_name.len, - file->f_path.dentry->d_name.name, mode); + if (trace_ocfs2_file_open_enabled()) { + struct dentry *dentry = file->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_open(inode, file, dentry, + oi->ip_blkno, + name.name.len, name.name.name, + mode); + release_dentry_name_snapshot(&name); + } if (file->f_mode & FMODE_WRITE) { status = dquot_initialize(inode); @@ -173,11 +180,17 @@ static int ocfs2_sync_file(struct file * tid_t commit_tid; bool needs_barrier = false; - trace_ocfs2_sync_file(inode, file, file->f_path.dentry, - oi->ip_blkno, - file->f_path.dentry->d_name.len, - file->f_path.dentry->d_name.name, - (unsigned long long)datasync); + if (trace_ocfs2_sync_file_enabled()) { + struct dentry *dentry = file->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_sync_file(inode, file, dentry, + oi->ip_blkno, + name.name.len, name.name.name, + (unsigned long long)datasync); + release_dentry_name_snapshot(&name); + } if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) return -EROFS; @@ -1126,15 +1139,19 @@ int ocfs2_setattr(struct mnt_idmap *idma int had_lock; struct ocfs2_lock_holder oh; - trace_ocfs2_setattr(inode, dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - dentry->d_name.len, dentry->d_name.name, - attr->ia_valid, - attr->ia_valid & ATTR_MODE ? attr->ia_mode : 0, - attr->ia_valid & ATTR_UID ? + if (trace_ocfs2_setattr_enabled()) { + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_setattr(inode, dentry, OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, attr->ia_valid, + attr->ia_valid & ATTR_MODE ? attr->ia_mode : 0, + attr->ia_valid & ATTR_UID ? from_kuid(&init_user_ns, attr->ia_uid) : 0, - attr->ia_valid & ATTR_GID ? + attr->ia_valid & ATTR_GID ? from_kgid(&init_user_ns, attr->ia_gid) : 0); + release_dentry_name_snapshot(&name); + } /* ensuring we don't even attempt to truncate a symlink */ if (S_ISLNK(inode->i_mode)) @@ -2380,11 +2397,17 @@ static ssize_t ocfs2_file_write_iter(str int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; - trace_ocfs2_file_write_iter(inode, file, file->f_path.dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - file->f_path.dentry->d_name.len, - file->f_path.dentry->d_name.name, - (unsigned int)from->nr_segs); /* GRRRRR */ + if (trace_ocfs2_file_write_iter_enabled()) { + struct dentry *dentry = file->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_write_iter(inode, file, dentry, + OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, + (unsigned int)from->nr_segs); + release_dentry_name_snapshot(&name); + } if (!direct_io && nowait) return -EOPNOTSUPP; @@ -2530,17 +2553,16 @@ static ssize_t ocfs2_file_read_iter(stru int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; - trace_ocfs2_file_read_iter(inode, filp, filp->f_path.dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - filp->f_path.dentry->d_name.len, - filp->f_path.dentry->d_name.name, - to->nr_segs); /* GRRRRR */ - - - if (!inode) { - ret = -EINVAL; - mlog_errno(ret); - goto bail; + if (trace_ocfs2_file_read_iter_enabled()) { + struct dentry *dentry = filp->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_read_iter(inode, filp, dentry, + OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, + to->nr_segs); + release_dentry_name_snapshot(&name); } if (!direct_io && nowait) @@ -2612,11 +2634,17 @@ static ssize_t ocfs2_file_splice_read(st ssize_t ret = 0; int lock_level = 0; - trace_ocfs2_file_splice_read(inode, in, in->f_path.dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - in->f_path.dentry->d_name.len, - in->f_path.dentry->d_name.name, - flags); + if (trace_ocfs2_file_splice_read_enabled()) { + struct dentry *dentry = in->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_splice_read(inode, in, dentry, + OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, + flags); + release_dentry_name_snapshot(&name); + } /* * We're fine letting folks race truncates and extending writes with