[PATCH OLK-6.6 0/2] tracepoints: get correct superblock from dentry in event btrfs_sync_file()
[ Upstream commit a85b46db143fda5869e7d8df8f258ccef5fa1719 ] If overlay is used on top of btrfs, dentry->d_sb translates to overlay's super block and fsid assignment will lead to a crash. Use file_inode(file)->i_sb to always get btrfs_sb. The patch above introduced another problem and is fixed in the following patch: The trace event btrfs_sync_file() is called in an atomic context (all trace events are) and its call to dput(), which is needed due to the call to dget_parent(), can sleep, triggering a kernel splat. This can be reproduced by enabling the trace event and running btrfs/056 from fstests for example. The splat shown in dmesg is the following: [53.919] BUG: sleeping function called from invalid context at fs/dcache.c:970 [53.947] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 32773, name: xfs_io [53.988] preempt_count: 2, expected: 0 [53.967] RCU nest depth: 0, expected: 0 [53.943] Preemption disabled at: [53.944] [<0000000000000000>] 0x0 [54.078] CPU: 0 UID: 0 PID: 32773 Comm: xfs_io Tainted: G W 7.1.0-rc1-btrfs-next-232+ #1 PREEMPT(full) [54.070] Tainted: [W]=WARN [54.071] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [54.072] Call Trace: [54.074] <TASK> [54.076] dump_stack_lvl+0x56/0x80 [54.079] __might_resched.cold+0xd6/0x10f [54.072] dput.part.0+0x24/0x110 [54.078] trace_event_raw_event_btrfs_sync_file+0x75/0x140 [btrfs] [54.089] btrfs_sync_file+0x1ed/0x530 [btrfs] [54.087] ? __handle_mm_fault+0x8ae/0xed0 [54.089] btrfs_do_write_iter+0x172/0x210 [btrfs] [54.091] vfs_write+0x21f/0x450 [54.094] __x64_sys_pwrite64+0x8d/0xc0 [54.096] ? do_user_addr_fault+0x20c/0x670 [54.099] do_syscall_64+0x60/0xf20 [54.092] ? clear_bhb_loop+0x60/0xb0 [54.094] entry_SYSCALL_64_after_hwframe+0x76/0x7e So stop using dget_parent() and dput() and access the parent dentry directly as dentry->d_parent. This is also what ext4 is doing in its equivalent trace event ext4_sync_file_enter(). Filipe Manana (1): btrfs: tracepoints: fix sleep while in atomic context in btrfs_sync_file() Goldwyn Rodrigues (1): btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file() include/trace/events/btrfs.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) -- 2.34.1
From: Goldwyn Rodrigues <rgoldwyn@suse.de> stable inclusion from stable-v6.6.136 commit c09a7446aab5773f38d6abb25fce99b8e1dfbc97 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14618 CVE: CVE-2026-43117 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit a85b46db143fda5869e7d8df8f258ccef5fa1719 ] If overlay is used on top of btrfs, dentry->d_sb translates to overlay's super block and fsid assignment will lead to a crash. Use file_inode(file)->i_sb to always get btrfs_sb. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Pan Taixi <pantaixi1@huawei.com> --- include/trace/events/btrfs.h | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index f759109caeea..4fef4f8c3138 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -787,16 +787,19 @@ TRACE_EVENT(btrfs_sync_file, __field( int, datasync ) __field( u64, root_objectid ) ), TP_fast_assign( - const struct dentry *dentry = file->f_path.dentry; - const struct inode *inode = d_inode(dentry); + struct dentry *dentry = file_dentry(file); + struct inode *inode = file_inode(file); + struct dentry *parent = dget_parent(dentry); + struct inode *parent_inode = d_inode(parent); - TP_fast_assign_fsid(btrfs_sb(file->f_path.dentry->d_sb)); + dput(parent); + TP_fast_assign_fsid(btrfs_sb(inode->i_sb)); __entry->ino = btrfs_ino(BTRFS_I(inode)); - __entry->parent = btrfs_ino(BTRFS_I(d_inode(dentry->d_parent))); + __entry->parent = btrfs_ino(BTRFS_I(parent_inode)); __entry->datasync = datasync; __entry->root_objectid = BTRFS_I(inode)->root->root_key.objectid; ), -- 2.34.1
From: Filipe Manana <fdmanana@suse.com> mainline inclusion from mainline-v7.1-rc4 commit c73370c677646e86fc4b1780fb07027bdf847375 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14618 CVE: CVE-2026-43117 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The trace event btrfs_sync_file() is called in an atomic context (all trace events are) and its call to dput(), which is needed due to the call to dget_parent(), can sleep, triggering a kernel splat. This can be reproduced by enabling the trace event and running btrfs/056 from fstests for example. The splat shown in dmesg is the following: [53.919] BUG: sleeping function called from invalid context at fs/dcache.c:970 [53.947] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 32773, name: xfs_io [53.988] preempt_count: 2, expected: 0 [53.967] RCU nest depth: 0, expected: 0 [53.943] Preemption disabled at: [53.944] [<0000000000000000>] 0x0 [54.078] CPU: 0 UID: 0 PID: 32773 Comm: xfs_io Tainted: G W 7.1.0-rc1-btrfs-next-232+ #1 PREEMPT(full) [54.070] Tainted: [W]=WARN [54.071] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [54.072] Call Trace: [54.074] <TASK> [54.076] dump_stack_lvl+0x56/0x80 [54.079] __might_resched.cold+0xd6/0x10f [54.072] dput.part.0+0x24/0x110 [54.078] trace_event_raw_event_btrfs_sync_file+0x75/0x140 [btrfs] [54.089] btrfs_sync_file+0x1ed/0x530 [btrfs] [54.087] ? __handle_mm_fault+0x8ae/0xed0 [54.089] btrfs_do_write_iter+0x172/0x210 [btrfs] [54.091] vfs_write+0x21f/0x450 [54.094] __x64_sys_pwrite64+0x8d/0xc0 [54.096] ? do_user_addr_fault+0x20c/0x670 [54.099] do_syscall_64+0x60/0xf20 [54.092] ? clear_bhb_loop+0x60/0xb0 [54.094] entry_SYSCALL_64_after_hwframe+0x76/0x7e So stop using dget_parent() and dput() and access the parent dentry directly as dentry->d_parent. This is also what ext4 is doing in its equivalent trace event ext4_sync_file_enter(). Fixes: a85b46db143f ("btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()") Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Conflicts: include/trace/events/btrfs.h [Context conflicts due to unmerged commit 0f987c099d22 ("btrfs: tracepoints: use btrfs_root_id() to get the id of a root")] Signed-off-by: Pan Taixi <pantaixi1@huawei.com> --- include/trace/events/btrfs.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 4fef4f8c3138..b6346bcefd6b 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -789,14 +789,12 @@ TRACE_EVENT(btrfs_sync_file, ), TP_fast_assign( struct dentry *dentry = file_dentry(file); struct inode *inode = file_inode(file); - struct dentry *parent = dget_parent(dentry); - struct inode *parent_inode = d_inode(parent); + struct inode *parent_inode = d_inode(dentry->d_parent); - dput(parent); TP_fast_assign_fsid(btrfs_sb(inode->i_sb)); __entry->ino = btrfs_ino(BTRFS_I(inode)); __entry->parent = btrfs_ino(BTRFS_I(parent_inode)); __entry->datasync = datasync; __entry->root_objectid = -- 2.34.1
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