* [PATCH][next] btrfs: fix memory leak of path on error return path
@ 2019-07-02 14:10 Colin King
2019-07-04 16:37 ` David Sterba
0 siblings, 1 reply; 5+ messages in thread
From: Colin King @ 2019-07-02 14:10 UTC (permalink / raw)
To: Chris Mason, Josef Bacik, David Sterba, linux-btrfs
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently if the allocation of roots or tmp_ulist fails the error handling
does not free up the allocation of path causing a memory leak. Fix this by
freeing path with a call to btrfs_free_path before taking the error return
path.
Addresses-Coverity: ("Resource leak")
Fixes: 5911c8fe05c5 ("btrfs: fiemap: preallocate ulists for btrfs_check_shared")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
fs/btrfs/extent_io.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 1eb671c16ff1..d7f37a33d597 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4600,6 +4600,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
tmp_ulist = ulist_alloc(GFP_KERNEL);
if (!roots || !tmp_ulist) {
ret = -ENOMEM;
+ btrfs_free_path(path);
goto out_free_ulist;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH][next] btrfs: fix memory leak of path on error return path
2019-07-02 14:10 [PATCH][next] btrfs: fix memory leak of path on error return path Colin King
@ 2019-07-04 16:37 ` David Sterba
2019-07-04 16:47 ` Colin Ian King
2019-07-05 1:28 ` Anand Jain
0 siblings, 2 replies; 5+ messages in thread
From: David Sterba @ 2019-07-04 16:37 UTC (permalink / raw)
To: Colin King
Cc: Chris Mason, Josef Bacik, David Sterba, linux-btrfs,
kernel-janitors, linux-kernel
On Tue, Jul 02, 2019 at 03:10:28PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently if the allocation of roots or tmp_ulist fails the error handling
> does not free up the allocation of path causing a memory leak. Fix this by
> freeing path with a call to btrfs_free_path before taking the error return
> path.
>
> Addresses-Coverity: ("Resource leak")
Does this have an id, that coverity uses?
> Fixes: 5911c8fe05c5 ("btrfs: fiemap: preallocate ulists for btrfs_check_shared")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> fs/btrfs/extent_io.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 1eb671c16ff1..d7f37a33d597 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4600,6 +4600,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> tmp_ulist = ulist_alloc(GFP_KERNEL);
> if (!roots || !tmp_ulist) {
> ret = -ENOMEM;
> + btrfs_free_path(path);
This fixes only one leak, therere are more that I spotted while
reviewing this patch. The gotos from the while-loop jump to
out_free_list but that leave the path behind.
That's why the exit block is a better place for the cleanups. This
requires proper nesting of the cleanup calls, that's slightly
inconvenient in this case. The free_path is before call to
unlock_extent_cached so when the ordre is switched and free_path moved
to out_free_ulist, then all the leaks are addressed in one go.
Bummer that the leaks escaped sight of original patch author (me), 2
reviewers and now 1 fix reviewer.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][next] btrfs: fix memory leak of path on error return path
2019-07-04 16:37 ` David Sterba
@ 2019-07-04 16:47 ` Colin Ian King
2019-07-04 17:20 ` David Sterba
2019-07-05 1:28 ` Anand Jain
1 sibling, 1 reply; 5+ messages in thread
From: Colin Ian King @ 2019-07-04 16:47 UTC (permalink / raw)
To: dsterba, Chris Mason, Josef Bacik, David Sterba, linux-btrfs,
kernel-janitors, linux-kernel
On 04/07/2019 17:37, David Sterba wrote:
> On Tue, Jul 02, 2019 at 03:10:28PM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Currently if the allocation of roots or tmp_ulist fails the error handling
>> does not free up the allocation of path causing a memory leak. Fix this by
>> freeing path with a call to btrfs_free_path before taking the error return
>> path.
>>
>> Addresses-Coverity: ("Resource leak")
>
> Does this have an id, that coverity uses?
Not a public one that I know of. These are based on private scans I run
in Canonical.
>
>> Fixes: 5911c8fe05c5 ("btrfs: fiemap: preallocate ulists for btrfs_check_shared")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>> fs/btrfs/extent_io.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index 1eb671c16ff1..d7f37a33d597 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -4600,6 +4600,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>> tmp_ulist = ulist_alloc(GFP_KERNEL);
>> if (!roots || !tmp_ulist) {
>> ret = -ENOMEM;
>> + btrfs_free_path(path);
>
> This fixes only one leak, therere are more that I spotted while
> reviewing this patch. The gotos from the while-loop jump to
> out_free_list but that leave the path behind>
> That's why the exit block is a better place for the cleanups. This
> requires proper nesting of the cleanup calls, that's slightly
> inconvenient in this case. The free_path is before call to
> unlock_extent_cached so when the ordre is switched and free_path moved
> to out_free_ulist, then all the leaks are addressed in one go.
Oh, yes. Even static analysis missed that too!
>
> Bummer that the leaks escaped sight of original patch author (me), 2
> reviewers and now 1 fix reviewer.
>
Given that you can see more issues, I'll leave the fix in your capable
hands.
Colin
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][next] btrfs: fix memory leak of path on error return path
2019-07-04 16:47 ` Colin Ian King
@ 2019-07-04 17:20 ` David Sterba
0 siblings, 0 replies; 5+ messages in thread
From: David Sterba @ 2019-07-04 17:20 UTC (permalink / raw)
To: Colin Ian King
Cc: dsterba, Chris Mason, Josef Bacik, David Sterba, linux-btrfs,
kernel-janitors, linux-kernel
On Thu, Jul 04, 2019 at 05:47:50PM +0100, Colin Ian King wrote:
> >> tmp_ulist = ulist_alloc(GFP_KERNEL);
> >> if (!roots || !tmp_ulist) {
> >> ret = -ENOMEM;
> >> + btrfs_free_path(path);
> >
> > This fixes only one leak, therere are more that I spotted while
> > reviewing this patch. The gotos from the while-loop jump to
> > out_free_list but that leave the path behind>
> > That's why the exit block is a better place for the cleanups. This
> > requires proper nesting of the cleanup calls, that's slightly
> > inconvenient in this case. The free_path is before call to
> > unlock_extent_cached so when the ordre is switched and free_path moved
> > to out_free_ulist, then all the leaks are addressed in one go.
>
> Oh, yes. Even static analysis missed that too!
>
> > Bummer that the leaks escaped sight of original patch author (me), 2
> > reviewers and now 1 fix reviewer.
> >
> Given that you can see more issues, I'll leave the fix in your capable
> hands.
This
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4764,11 +4764,11 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
ret = emit_last_fiemap_cache(fieinfo, &cache);
free_extent_map(em);
out:
- btrfs_free_path(path);
unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
&cached_state);
out_free_ulist:
+ btrfs_free_path(path);
ulist_free(roots);
ulist_free(tmp_ulist);
return ret;
---
should fix it.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH][next] btrfs: fix memory leak of path on error return path
2019-07-04 16:37 ` David Sterba
2019-07-04 16:47 ` Colin Ian King
@ 2019-07-05 1:28 ` Anand Jain
1 sibling, 0 replies; 5+ messages in thread
From: Anand Jain @ 2019-07-05 1:28 UTC (permalink / raw)
To: dsterba, Colin King, Chris Mason, Josef Bacik, David Sterba,
linux-btrfs, kernel-janitors, linux-kernel
On 5/7/19 12:37 AM, David Sterba wrote:
> On Tue, Jul 02, 2019 at 03:10:28PM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Currently if the allocation of roots or tmp_ulist fails the error handling
>> does not free up the allocation of path causing a memory leak. Fix this by
>> freeing path with a call to btrfs_free_path before taking the error return
>> path.
>>
>> Addresses-Coverity: ("Resource leak")
>
> Does this have an id, that coverity uses?
>
>> Fixes: 5911c8fe05c5 ("btrfs: fiemap: preallocate ulists for btrfs_check_shared")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>> fs/btrfs/extent_io.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index 1eb671c16ff1..d7f37a33d597 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -4600,6 +4600,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>> tmp_ulist = ulist_alloc(GFP_KERNEL);
>> if (!roots || !tmp_ulist) {
>> ret = -ENOMEM;
>> + btrfs_free_path(path);
>
> This fixes only one leak, therere are more that I spotted while
> reviewing this patch. The gotos from the while-loop jump to
> out_free_list but that leave the path behind.
>
> That's why the exit block is a better place for the cleanups. This
> requires proper nesting of the cleanup calls, that's slightly
> inconvenient in this case. The free_path is before call to
> unlock_extent_cached so when the ordre is switched and free_path moved
> to out_free_ulist, then all the leaks are addressed in one go.
>
> Bummer that the leaks escaped sight of original patch author (me), 2
> reviewers and now 1 fix reviewer.
>
There is no goto out_free_ulist inside the while loop; where do you see
that? I did git pull again and checked.
4664 while (!end) {
::
4726 goto out_free;
::
4748 goto out;
::
4759 goto out_free;
::
4761 }
^ permalink raw reply [flat|nested] 5+ messages in thread
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2019-07-02 14:10 [PATCH][next] btrfs: fix memory leak of path on error return path Colin King
2019-07-04 16:37 ` David Sterba
2019-07-04 16:47 ` Colin Ian King
2019-07-04 17:20 ` David Sterba
2019-07-05 1:28 ` Anand Jain
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