The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
47311db8e8f3 ("tracefs: Only clobber mode/uid/gid on remount if asked") 851e99ebeec3 ("tracefs: Set the group ownership in apply_options() not parse_options()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 47311db8e8f33011d90dee76b39c8886120cdda4 Mon Sep 17 00:00:00 2001 From: Brian Norris briannorris@chromium.org Date: Fri, 26 Aug 2022 17:44:17 -0700 Subject: [PATCH] tracefs: Only clobber mode/uid/gid on remount if asked
Users may have explicitly configured their tracefs permissions; we shouldn't overwrite those just because a second mount appeared.
Only clobber if the options were provided at mount time.
Note: the previous behavior was especially surprising in the presence of automounted /sys/kernel/debug/tracing/.
Existing behavior:
## Pre-existing status: tracefs is 0755. # stat -c '%A' /sys/kernel/tracing/ drwxr-xr-x
## (Re)trigger the automount. # umount /sys/kernel/debug/tracing # stat -c '%A' /sys/kernel/debug/tracing/. drwx------
## Unexpected: the automount changed mode for other mount instances. # stat -c '%A' /sys/kernel/tracing/ drwx------
New behavior (after this change):
## Pre-existing status: tracefs is 0755. # stat -c '%A' /sys/kernel/tracing/ drwxr-xr-x
## (Re)trigger the automount. # umount /sys/kernel/debug/tracing # stat -c '%A' /sys/kernel/debug/tracing/. drwxr-xr-x
## Expected: the automount does not change other mount instances. # stat -c '%A' /sys/kernel/tracing/ drwxr-xr-x
Link: https://lkml.kernel.org/r/20220826174353.2.Iab6e5ea57963d6deca5311b27fb72267...
Cc: stable@vger.kernel.org Fixes: 4282d60689d4f ("tracefs: Add new tracefs file system") Signed-off-by: Brian Norris briannorris@chromium.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 81d26abf486f..da85b3979195 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -141,6 +141,8 @@ struct tracefs_mount_opts { kuid_t uid; kgid_t gid; umode_t mode; + /* Opt_* bitfield. */ + unsigned int opts; };
enum { @@ -241,6 +243,7 @@ static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts) kgid_t gid; char *p;
+ opts->opts = 0; opts->mode = TRACEFS_DEFAULT_MODE;
while ((p = strsep(&data, ",")) != NULL) { @@ -275,24 +278,36 @@ static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts) * but traditionally tracefs has ignored all mount options */ } + + opts->opts |= BIT(token); }
return 0; }
-static int tracefs_apply_options(struct super_block *sb) +static int tracefs_apply_options(struct super_block *sb, bool remount) { struct tracefs_fs_info *fsi = sb->s_fs_info; struct inode *inode = d_inode(sb->s_root); struct tracefs_mount_opts *opts = &fsi->mount_opts;
- inode->i_mode &= ~S_IALLUGO; - inode->i_mode |= opts->mode; + /* + * On remount, only reset mode/uid/gid if they were provided as mount + * options. + */ + + if (!remount || opts->opts & BIT(Opt_mode)) { + inode->i_mode &= ~S_IALLUGO; + inode->i_mode |= opts->mode; + }
- inode->i_uid = opts->uid; + if (!remount || opts->opts & BIT(Opt_uid)) + inode->i_uid = opts->uid;
- /* Set all the group ids to the mount option */ - set_gid(sb->s_root, opts->gid); + if (!remount || opts->opts & BIT(Opt_gid)) { + /* Set all the group ids to the mount option */ + set_gid(sb->s_root, opts->gid); + }
return 0; } @@ -307,7 +322,7 @@ static int tracefs_remount(struct super_block *sb, int *flags, char *data) if (err) goto fail;
- tracefs_apply_options(sb); + tracefs_apply_options(sb, true);
fail: return err; @@ -359,7 +374,7 @@ static int trace_fill_super(struct super_block *sb, void *data, int silent)
sb->s_op = &tracefs_super_operations;
- tracefs_apply_options(sb); + tracefs_apply_options(sb, false);
return 0;
Hi Greg,
On Fri, Sep 9, 2022 at 11:31 AM gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Did something go wrong in your automation? The same patch applies cleanly to me (currently, on top of v5.15.67).
Possible dependencies:
47311db8e8f3 ("tracefs: Only clobber mode/uid/gid on remount if asked")
That's $subject patch. OK, so not that one.
851e99ebeec3 ("tracefs: Set the group ownership in apply_options() not parse_options()")
That one *is* a dependency, but it's already backported to 5.15.y as of several months ago:
commit 6db927ce66ac68bf732f0b14190791458e75047a Author: Steven Rostedt (Google) rostedt@goodmis.org AuthorDate: Fri Feb 25 15:34:26 2022 -0500 Commit: Greg Kroah-Hartman gregkh@linuxfoundation.org CommitDate: Wed Mar 2 11:48:05 2022 +0100
tracefs: Set the group ownership in apply_options() not parse_options()
commit 851e99ebeec3f4a672bb5010cf1ece095acee447 upstream.
So I'm not sure what to do to fix the backporting, other than ping back here.
I think the same applies to the 5.10.y rejection notice, and possibly a few others.
Brian
On Mon, Sep 12, 2022 at 03:23:42PM -0700, Brian Norris wrote:
Hi Greg,
On Fri, Sep 9, 2022 at 11:31 AM gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Did something go wrong in your automation? The same patch applies cleanly to me (currently, on top of v5.15.67).
Possible dependencies:
47311db8e8f3 ("tracefs: Only clobber mode/uid/gid on remount if asked")
That's $subject patch. OK, so not that one.
851e99ebeec3 ("tracefs: Set the group ownership in apply_options() not parse_options()")
That one *is* a dependency, but it's already backported to 5.15.y as of several months ago:
commit 6db927ce66ac68bf732f0b14190791458e75047a Author: Steven Rostedt (Google) rostedt@goodmis.org AuthorDate: Fri Feb 25 15:34:26 2022 -0500 Commit: Greg Kroah-Hartman gregkh@linuxfoundation.org CommitDate: Wed Mar 2 11:48:05 2022 +0100
tracefs: Set the group ownership in apply_options() not parse_options() commit 851e99ebeec3f4a672bb5010cf1ece095acee447 upstream.
So I'm not sure what to do to fix the backporting, other than ping back here.
I think the same applies to the 5.10.y rejection notice, and possibly a few others.
Here is what patch says:
Applying tracefs-only-clobber-mode-uid-gid-on-remount-if-asked.patch to linux-5.15.y Applying patch tracefs-only-clobber-mode-uid-gid-on-remount-if-asked.patch patching file fs/tracefs/inode.c Hunk #3 FAILED at 278. 1 out of 5 hunks FAILED -- rejects in file fs/tracefs/inode.c Patch tracefs-only-clobber-mode-uid-gid-on-remount-if-asked.patch does not apply (enforce with -f) quilt returned 1, with 0 fuzz and 1 rejects
How did you apply the patch to 5.15.y that worked?
thanks,
greg k-h
On Tue, Sep 13, 2022 at 4:34 AM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
Here is what patch says:
Applying tracefs-only-clobber-mode-uid-gid-on-remount-if-asked.patch to linux-5.15.y Applying patch tracefs-only-clobber-mode-uid-gid-on-remount-if-asked.patch patching file fs/tracefs/inode.c Hunk #3 FAILED at 278. 1 out of 5 hunks FAILED -- rejects in file fs/tracefs/inode.c Patch tracefs-only-clobber-mode-uid-gid-on-remount-if-asked.patch does not apply (enforce with -f) quilt returned 1, with 0 fuzz and 1 rejects
How did you apply the patch to 5.15.y that worked?
Hmm, I suppose I have 'git am' doing 3-way merges for me, which resolve OK:
$ curl https://lore.kernel.org/all/166274826116451@kroah.com/raw | git am - % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 6614 100 6614 0 0 27768 0 --:--:-- --:--:-- --:--:-- 27789 Applying: FAILED: patch "[PATCH] tracefs: Only clobber mode/uid/gid on remount if asked" failed to apply to 5.15-stable tree Using index info to reconstruct a base tree... M fs/tracefs/inode.c Falling back to patching base and 3-way merge... Auto-merging fs/tracefs/inode.c
And originally, I guess I was testing 'git cherry-pick', not literally this patch. That also does some "auto-merging":
$ git cherry-pick 47311db8e8f33011d90dee76b39c8886120cdda4 Auto-merging fs/tracefs/inode.c [detached HEAD e9f574cc9df9] tracefs: Only clobber mode/uid/gid on remount if asked Date: Fri Aug 26 17:44:17 2022 -0700 1 file changed, 23 insertions(+), 8 deletions(-)
I'll generate a clean patch based on the above, but it'll look awfully similar. (I think there's a single line of context that looks different, a few lines away.) Stay tuned.
Brian
linux-stable-mirror@lists.linaro.org