* [PATCH] ovl: inode reference leak in "ovl_is_inuse" true case.
@ 2020-06-15 15:56 youngjun
2020-06-15 16:45 ` Amir Goldstein
2020-06-16 4:46 ` [PATCH] ovl: inode reference leak in ovl_is_inuse " youngjun
0 siblings, 2 replies; 4+ messages in thread
From: youngjun @ 2020-06-15 15:56 UTC (permalink / raw)
To: Miklos Szeredi; +Cc: linux-unionfs, linux-kernel, youngjun
When "ovl_is_inuse" true case, trap inode reference not put.
Signed-off-by: youngjun <her0gyugyu@gmail.com>
---
fs/overlayfs/super.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 91476bc422f9..8837fc1ec3be 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1499,8 +1499,10 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
if (ovl_is_inuse(stack[i].dentry)) {
err = ovl_report_in_use(ofs, "lowerdir");
- if (err)
+ if (err) {
+ iput(trap);
goto out;
+ }
}
mnt = clone_private_mount(&stack[i]);
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ovl: inode reference leak in "ovl_is_inuse" true case.
2020-06-15 15:56 [PATCH] ovl: inode reference leak in "ovl_is_inuse" true case youngjun
@ 2020-06-15 16:45 ` Amir Goldstein
2020-06-16 4:46 ` [PATCH] ovl: inode reference leak in ovl_is_inuse " youngjun
1 sibling, 0 replies; 4+ messages in thread
From: Amir Goldstein @ 2020-06-15 16:45 UTC (permalink / raw)
To: youngjun; +Cc: Miklos Szeredi, overlayfs, linux-kernel
On Mon, Jun 15, 2020 at 6:57 PM youngjun <her0gyugyu@gmail.com> wrote:
>
> When "ovl_is_inuse" true case, trap inode reference not put.
>
> Signed-off-by: youngjun <her0gyugyu@gmail.com>
Fixes: 0be0bfd2de9d ("ovl: fix regression caused by overlapping layers
detection")
Cc: <stable@vger.kernel.org> # v4.19+
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
> ---
> fs/overlayfs/super.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 91476bc422f9..8837fc1ec3be 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -1499,8 +1499,10 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
>
> if (ovl_is_inuse(stack[i].dentry)) {
> err = ovl_report_in_use(ofs, "lowerdir");
> - if (err)
> + if (err) {
> + iput(trap);
> goto out;
> + }
> }
>
Urgh! I moved this ovl_is_inuse() after ovl_setup_trap() for a reason, but I did
not explain why. While we are fixing the bug, it would be nice to add a comment
above ovl_setup_trap():
/*
* Check if lower root conflicts with this overlay layers before checking
* if it is in-use as upperdir/workdir of "another" mount, because we do
* not bother to check in ovl_is_inuse() if the upperdir/workdir is in fact
* in-use by our upperdir/workdir.
*/
Thanks,
Amir.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] ovl: inode reference leak in ovl_is_inuse true case.
2020-06-15 15:56 [PATCH] ovl: inode reference leak in "ovl_is_inuse" true case youngjun
2020-06-15 16:45 ` Amir Goldstein
@ 2020-06-16 4:46 ` youngjun
2020-06-16 5:33 ` Amir Goldstein
1 sibling, 1 reply; 4+ messages in thread
From: youngjun @ 2020-06-16 4:46 UTC (permalink / raw)
To: amir73il; +Cc: Miklos Szeredi, linux-unionfs, linux-kernel, youngjun
When "ovl_is_inuse" true case, trap inode reference not put.
plus adding the comment explaining sequence of
ovl_is_inuse after ovl_setup_trap.
Signed-off-by: youngjun <her0gyugyu@gmail.com>
---
fs/overlayfs/super.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 91476bc422f9..0396793dadb8 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1029,6 +1029,12 @@ static const struct xattr_handler *ovl_xattr_handlers[] = {
NULL
};
+/*
+ * Check if lower root conflicts with this overlay layers before checking
+ * if it is in-use as upperdir/workdir of "another" mount, because we do
+ * not bother to check in ovl_is_inuse() if the upperdir/workdir is in fact
+ * in-use by our upperdir/workdir.
+ */
static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
struct inode **ptrap, const char *name)
{
@@ -1499,8 +1505,10 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
if (ovl_is_inuse(stack[i].dentry)) {
err = ovl_report_in_use(ofs, "lowerdir");
- if (err)
+ if (err) {
+ iput(trap);
goto out;
+ }
}
mnt = clone_private_mount(&stack[i]);
--
2.17.1
Thank you for comment Amir. I modified patch as you said.
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ovl: inode reference leak in ovl_is_inuse true case.
2020-06-16 4:46 ` [PATCH] ovl: inode reference leak in ovl_is_inuse " youngjun
@ 2020-06-16 5:33 ` Amir Goldstein
0 siblings, 0 replies; 4+ messages in thread
From: Amir Goldstein @ 2020-06-16 5:33 UTC (permalink / raw)
To: youngjun; +Cc: Miklos Szeredi, overlayfs, linux-kernel
Hi youngjun!
Thank you for your patch.
You asked for guidance about posting patch revisions so let me repeat
my comment in a more clear way (see below).
On Tue, Jun 16, 2020 at 7:46 AM youngjun <her0gyugyu@gmail.com> wrote:
>
When posting a revision of a patch already posted, the practice
is to use the subject prefix [PATCH v2].
This will be auto generated for you with -v option for git format-patch.
Also, it is not valuable to CC LKML on patches with such a narrow
scope. The only relevant CC for this patch is the overlayfs list,
overlayfs maintainer and developers that reviewed v1 (me in that case).
> When "ovl_is_inuse" true case, trap inode reference not put.
> plus adding the comment explaining sequence of
> ovl_is_inuse after ovl_setup_trap.
>
Please add these lines to the bottom of commit message:
(They help the stable tree maintainers know that patch
should be picked up and to which stable tree)
Fixes: 0be0bfd2de9d ("ovl: fix regression caused by overlapping layers..")
Cc: <stable@vger.kernel.org> # v4.19+
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: youngjun <her0gyugyu@gmail.com>
> ---
> fs/overlayfs/super.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 91476bc422f9..0396793dadb8 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -1029,6 +1029,12 @@ static const struct xattr_handler *ovl_xattr_handlers[] = {
> NULL
> };
>
> +/*
> + * Check if lower root conflicts with this overlay layers before checking
> + * if it is in-use as upperdir/workdir of "another" mount, because we do
> + * not bother to check in ovl_is_inuse() if the upperdir/workdir is in fact
> + * in-use by our upperdir/workdir.
> + */
Sorry for not being clear about this comment.
I meant it should come before the call to ovl_setup_trap() in
ovl_get_layers(). It is not true in general that we always call ovl_setup_trap()
before ovl_is_inuse(). It is only true and relevant for checking lower layers.
If anything I wrote is not clear, do not hesitate to ask for more clarification.
Thanks,
Amir.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-06-15 15:56 [PATCH] ovl: inode reference leak in "ovl_is_inuse" true case youngjun
2020-06-15 16:45 ` Amir Goldstein
2020-06-16 4:46 ` [PATCH] ovl: inode reference leak in ovl_is_inuse " youngjun
2020-06-16 5:33 ` Amir Goldstein
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