From: Linus Torvalds <torvalds(a)linux-foundation.org>
The eventfs_find_events() code tries to walk up the tree to find the
event directory that a dentry belongs to, in order to then find the
eventfs inode that is associated with that event directory.
However, it uses an odd combination of walking the dentry parent,
looking up the eventfs inode associated with that, and then looking up
the dentry from there. Repeat.
But the code shouldn't have back-pointers to dentries in the first
place, and it should just walk the dentry parenthood chain directly.
Similarly, 'set_top_events_ownership()' looks up the dentry from the
eventfs inode, but the only reason it wants a dentry is to look up the
superblock in order to look up the root dentry.
But it already has the real filesystem inode, which has that same
superblock pointer. So just pass in the superblock pointer using the
information that's already there, instead of looking up extraneous data
that is irrelevant.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.san…
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.638645365@goodmis…
Cc: stable(a)vger.kernel.org
Cc: Masami Hiramatsu <mhiramat(a)kernel.org>
Cc: Mark Rutland <mark.rutland(a)arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
Cc: Christian Brauner <brauner(a)kernel.org>
Cc: Al Viro <viro(a)ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher(a)broadcom.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
fs/tracefs/event_inode.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 824b1811e342..e9819d719d2a 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -156,33 +156,30 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
return ret;
}
-static void update_top_events_attr(struct eventfs_inode *ei, struct dentry *dentry)
+static void update_top_events_attr(struct eventfs_inode *ei, struct super_block *sb)
{
- struct inode *inode;
+ struct inode *root;
/* Only update if the "events" was on the top level */
if (!ei || !(ei->attr.mode & EVENTFS_TOPLEVEL))
return;
/* Get the tracefs root inode. */
- inode = d_inode(dentry->d_sb->s_root);
- ei->attr.uid = inode->i_uid;
- ei->attr.gid = inode->i_gid;
+ root = d_inode(sb->s_root);
+ ei->attr.uid = root->i_uid;
+ ei->attr.gid = root->i_gid;
}
static void set_top_events_ownership(struct inode *inode)
{
struct tracefs_inode *ti = get_tracefs(inode);
struct eventfs_inode *ei = ti->private;
- struct dentry *dentry;
/* The top events directory doesn't get automatically updated */
if (!ei || !ei->is_events || !(ei->attr.mode & EVENTFS_TOPLEVEL))
return;
- dentry = ei->dentry;
-
- update_top_events_attr(ei, dentry);
+ update_top_events_attr(ei, inode->i_sb);
if (!(ei->attr.mode & EVENTFS_SAVE_UID))
inode->i_uid = ei->attr.uid;
@@ -235,8 +232,10 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
mutex_lock(&eventfs_mutex);
do {
- /* The parent always has an ei, except for events itself */
- ei = dentry->d_parent->d_fsdata;
+ // The parent is stable because we do not do renames
+ dentry = dentry->d_parent;
+ // ... and directories always have d_fsdata
+ ei = dentry->d_fsdata;
/*
* If the ei is being freed, the ownership of the children
@@ -246,12 +245,11 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
ei = NULL;
break;
}
-
- dentry = ei->dentry;
+ // Walk upwards until you find the events inode
} while (!ei->is_events);
mutex_unlock(&eventfs_mutex);
- update_top_events_attr(ei, dentry);
+ update_top_events_attr(ei, dentry->d_sb);
return ei;
}
--
2.43.0
From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org>
eventfs uses the tracefs_inode and assumes that it's already initialized
to zero. That is, it doesn't set fields to zero (like ti->private) after
getting its tracefs_inode. This causes bugs due to stale values.
Just initialize the entire structure to zero on allocation so there isn't
any more surprises.
This is a partial fix to access to ti->private. The assignment still needs
to be made before the dentry is instantiated.
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.315825944@goodmis…
Cc: stable(a)vger.kernel.org
Cc: Masami Hiramatsu <mhiramat(a)kernel.org>
Cc: Mark Rutland <mark.rutland(a)arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
Cc: Christian Brauner <brauner(a)kernel.org>
Cc: Al Viro <viro(a)ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher(a)broadcom.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang(a)intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com
Suggested-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
fs/tracefs/inode.c | 6 ++++--
fs/tracefs/internal.h | 3 ++-
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index e1b172c0e091..888e42087847 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -38,8 +38,6 @@ static struct inode *tracefs_alloc_inode(struct super_block *sb)
if (!ti)
return NULL;
- ti->flags = 0;
-
return &ti->vfs_inode;
}
@@ -779,7 +777,11 @@ static void init_once(void *foo)
{
struct tracefs_inode *ti = (struct tracefs_inode *) foo;
+ /* inode_init_once() calls memset() on the vfs_inode portion */
inode_init_once(&ti->vfs_inode);
+
+ /* Zero out the rest */
+ memset_after(ti, 0, vfs_inode);
}
static int __init tracefs_init(void)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 91c2bf0b91d9..7d84349ade87 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -11,9 +11,10 @@ enum {
};
struct tracefs_inode {
+ struct inode vfs_inode;
+ /* The below gets initialized with memset_after(ti, 0, vfs_inode) */
unsigned long flags;
void *private;
- struct inode vfs_inode;
};
/*
--
2.43.0
From: Vincent Donnefort <vdonnefort(a)google.com>
The return type for ring_buffer_poll_wait() is __poll_t. This is behind
the scenes an unsigned where we can set event bits. In case of a
non-allocated CPU, we do return instead -EINVAL (0xffffffea). Lucky us,
this ends up setting few error bits (EPOLLERR | EPOLLHUP | EPOLLNVAL), so
user-space at least is aware something went wrong.
Nonetheless, this is an incorrect code. Replace that -EINVAL with a
proper EPOLLERR to clean that output. As this doesn't change the
behaviour, there's no need to treat this change as a bug fix.
Link: https://lore.kernel.org/linux-trace-kernel/20240131140955.3322792-1-vdonnef…
Cc: stable(a)vger.kernel.org
Fixes: 6721cb6002262 ("ring-buffer: Do not poll non allocated cpu buffers")
Signed-off-by: Vincent Donnefort <vdonnefort(a)google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
kernel/trace/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 13aaf5e85b81..fd4bfe3ecf01 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -944,7 +944,7 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
full = 0;
} else {
if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return -EINVAL;
+ return EPOLLERR;
cpu_buffer = buffer->buffers[cpu];
work = &cpu_buffer->irq_work;
--
2.43.0
On Thu, Feb 1, 2024 at 6:21 PM Sasha Levin <sashal(a)kernel.org> wrote:
> This is a note to let you know that I've just added the patch titled
>
> Hexagon: Make pfn accessors statics inlines
>
> to the 6.1-stable tree which can be found at:
> http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
>
> The filename of the patch is:
> hexagon-make-pfn-accessors-statics-inlines.patch
> and it can be found in the queue-6.1 subdirectory.
>
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable(a)vger.kernel.org> know about it.
Please drop this patch from the stable trees, it is not a regression
and there are bugs in the patch.
Yours,
Linus Walleij
On Thu, Feb 1, 2024 at 6:29 PM Sasha Levin <sashal(a)kernel.org> wrote:
> This is a note to let you know that I've just added the patch titled
>
> Hexagon: Make pfn accessors statics inlines
>
> to the 5.15-stable tree which can be found at:
> http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
>
> The filename of the patch is:
> hexagon-make-pfn-accessors-statics-inlines.patch
> and it can be found in the queue-5.15 subdirectory.
>
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable(a)vger.kernel.org> know about it.
Please drop this patch from the stable trees, it is not a regression
and there are bugs in the patch.
Yours,
Linus Walleij
Currently, the timerlat's hrtimer is initialized at the first read of
timerlat_fd, and destroyed at close(). It works, but it causes an error
if the user program open() and close() the file without reading.
Move hrtimer_init to timerlat_fd open() to avoid this problem.
No functional changes.
Fixes: e88ed227f639 ("tracing/timerlat: Add user-space interface")
Signed-off-by: Daniel Bristot de Oliveira <bristot(a)kernel.org>
---
kernel/trace/trace_osnoise.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index bd0d01d00fb9..a8e28f9b9271 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -2444,6 +2444,9 @@ static int timerlat_fd_open(struct inode *inode, struct file *file)
tlat = this_cpu_tmr_var();
tlat->count = 0;
+ hrtimer_init(&tlat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
+ tlat->timer.function = timerlat_irq;
+
migrate_enable();
return 0;
};
@@ -2526,9 +2529,6 @@ timerlat_fd_read(struct file *file, char __user *ubuf, size_t count,
tlat->tracing_thread = false;
tlat->kthread = current;
- hrtimer_init(&tlat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
- tlat->timer.function = timerlat_irq;
-
/* Annotate now to drift new period */
tlat->abs_period = hrtimer_cb_get_time(&tlat->timer);
--
2.43.0
Hi Sasha,
On Thu, Feb 1, 2024 at 5:58 PM Sasha Levin <sashal(a)kernel.org> wrote:
> This is a note to let you know that I've just added the patch titled
>
> Hexagon: Make pfn accessors statics inlines
>
> to the 6.7-stable tree which can be found at:
> http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
>
> The filename of the patch is:
> hexagon-make-pfn-accessors-statics-inlines.patch
> and it can be found in the queue-6.7 subdirectory.
>
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable(a)vger.kernel.org> know about it.
Please drop this patch from the stable queue, it is not a regression
and we found bugs in the patch as well.
Yours,
Linus Walleij