* Re: [PATCH] btrfs: initialize variable cancel
2022-01-21 13:45 [PATCH] btrfs: initialize variable cancel trix
@ 2022-01-21 15:40 ` Filipe Manana
2022-01-21 21:50 ` Anand Jain
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Filipe Manana @ 2022-01-21 15:40 UTC (permalink / raw)
To: trix
Cc: clm, josef, dsterba, nathan, ndesaulniers, anand.jain,
linux-btrfs, linux-kernel, llvm
On Fri, Jan 21, 2022 at 05:45:22AM -0800, trix@redhat.com wrote:
> From: Tom Rix <trix@redhat.com>
>
> Clang static analysis reports this problem
> ioctl.c:3333:8: warning: 3rd function call argument is an
> uninitialized value
> ret = exclop_start_or_cancel_reloc(fs_info,
>
> cancel is only set in one branch of an if-check and is
> always used. So initialize to false.
>
> Fixes: 1a15eb724aae ("btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls")
> Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Could use a more precise subject like for example:
"btrfs: fix use of uninitialized variable at rm device ioctl"
Anyway, it looks good.
Thanks.
> ---
> fs/btrfs/ioctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 190ad8af4f45a..26e82379747f8 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3308,7 +3308,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
> struct block_device *bdev = NULL;
> fmode_t mode;
> int ret;
> - bool cancel;
> + bool cancel = false;
>
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
> --
> 2.26.3
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] btrfs: initialize variable cancel
2022-01-21 13:45 [PATCH] btrfs: initialize variable cancel trix
2022-01-21 15:40 ` Filipe Manana
@ 2022-01-21 21:50 ` Anand Jain
2022-01-24 19:49 ` David Sterba
2022-01-25 5:04 ` Wang Yugui
3 siblings, 0 replies; 7+ messages in thread
From: Anand Jain @ 2022-01-21 21:50 UTC (permalink / raw)
To: trix, clm, josef, dsterba, nathan, ndesaulniers
Cc: linux-btrfs, linux-kernel, llvm
On 21/01/2022 21:45, trix@redhat.com wrote:
> From: Tom Rix <trix@redhat.com>
>
> Clang static analysis reports this problem
> ioctl.c:3333:8: warning: 3rd function call argument is an
> uninitialized value
> ret = exclop_start_or_cancel_reloc(fs_info,
>
> cancel is only set in one branch of an if-check and is
> always used. So initialize to false.
>
> Fixes: 1a15eb724aae ("btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls")
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
> fs/btrfs/ioctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 190ad8af4f45a..26e82379747f8 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3308,7 +3308,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
> struct block_device *bdev = NULL;
> fmode_t mode;
> int ret;
> - bool cancel;
> + bool cancel = false;
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Thanks,
Anand
>
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] btrfs: initialize variable cancel
2022-01-21 13:45 [PATCH] btrfs: initialize variable cancel trix
2022-01-21 15:40 ` Filipe Manana
2022-01-21 21:50 ` Anand Jain
@ 2022-01-24 19:49 ` David Sterba
2022-01-25 5:04 ` Wang Yugui
3 siblings, 0 replies; 7+ messages in thread
From: David Sterba @ 2022-01-24 19:49 UTC (permalink / raw)
To: trix
Cc: clm, josef, dsterba, nathan, ndesaulniers, anand.jain,
linux-btrfs, linux-kernel, llvm
On Fri, Jan 21, 2022 at 05:45:22AM -0800, trix@redhat.com wrote:
> From: Tom Rix <trix@redhat.com>
>
> Clang static analysis reports this problem
> ioctl.c:3333:8: warning: 3rd function call argument is an
> uninitialized value
> ret = exclop_start_or_cancel_reloc(fs_info,
>
> cancel is only set in one branch of an if-check and is
> always used. So initialize to false.
>
> Fixes: 1a15eb724aae ("btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls")
> Signed-off-by: Tom Rix <trix@redhat.com>
Added to misc-next, with the updted subject line, thanks.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] btrfs: initialize variable cancel
2022-01-21 13:45 [PATCH] btrfs: initialize variable cancel trix
` (2 preceding siblings ...)
2022-01-24 19:49 ` David Sterba
@ 2022-01-25 5:04 ` Wang Yugui
2022-01-25 8:30 ` Johannes Thumshirn
3 siblings, 1 reply; 7+ messages in thread
From: Wang Yugui @ 2022-01-25 5:04 UTC (permalink / raw)
To: trix; +Cc: linux-btrfs
Hi,
Mabye we should enable '-Wmaybe-uninitialized' for btrfs 'make W=1'.
There is another warning reproted by '-Wmaybe-uninitialized'
in btrfs misc-next.
fs/btrfs/zoned.c:273:28: warning: ‘zno’ may be used uninitialized in this function [-Wmaybe-uninitialized]
memcpy(zinfo->zone_cache + zno, zones,
^
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index cec88a6..f1052ce 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -2,6 +2,7 @@
# Subset of W=1 warnings
subdir-ccflags-y += -Wextra -Wunused -Wno-unused-parameter
+subdir-ccflags-y += -Wmaybe-uninitialized
subdir-ccflags-y += -Wmissing-declarations
subdir-ccflags-y += -Wmissing-format-attribute
subdir-ccflags-y += -Wmissing-prototypes
Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2022/01/25
> From: Tom Rix <trix@redhat.com>
>
> Clang static analysis reports this problem
> ioctl.c:3333:8: warning: 3rd function call argument is an
> uninitialized value
> ret = exclop_start_or_cancel_reloc(fs_info,
>
> cancel is only set in one branch of an if-check and is
> always used. So initialize to false.
>
> Fixes: 1a15eb724aae ("btrfs: use btrfs_get_dev_args_from_path in dev removal ioctls")
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
> fs/btrfs/ioctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 190ad8af4f45a..26e82379747f8 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3308,7 +3308,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
> struct block_device *bdev = NULL;
> fmode_t mode;
> int ret;
> - bool cancel;
> + bool cancel = false;
>
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
> --
> 2.26.3
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] btrfs: initialize variable cancel
2022-01-25 5:04 ` Wang Yugui
@ 2022-01-25 8:30 ` Johannes Thumshirn
2022-01-25 13:27 ` David Sterba
0 siblings, 1 reply; 7+ messages in thread
From: Johannes Thumshirn @ 2022-01-25 8:30 UTC (permalink / raw)
To: wangyugui, trix; +Cc: linux-btrfs
On Tue, 2022-01-25 at 13:04 +0800, Wang Yugui wrote:
> Hi,
>
> Mabye we should enable '-Wmaybe-uninitialized' for btrfs 'make W=1'.
>
> There is another warning reproted by '-Wmaybe-uninitialized'
> in btrfs misc-next.
>
> fs/btrfs/zoned.c:273:28: warning: ‘zno’ may be used uninitialized in
> this function [-Wmaybe-uninitialized]
> memcpy(zinfo->zone_cache + zno, zones,
> ^
Isn't that one a false positive?
u32 zno;
[...]
/* Check cache */
if (zinfo->zone_cache) {
unsigned int i;
ASSERT(IS_ALIGNED(pos, zinfo->zone_size));
zno = pos >> zinfo->zone_size_shift;
[...]
}
[...]
/* Populate cache */
if (zinfo->zone_cache)
memcpy(zinfo->zone_cache + zno, zones,
sizeof(*zinfo->zone_cache) * *nr_zones);
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] btrfs: initialize variable cancel
2022-01-25 8:30 ` Johannes Thumshirn
@ 2022-01-25 13:27 ` David Sterba
0 siblings, 0 replies; 7+ messages in thread
From: David Sterba @ 2022-01-25 13:27 UTC (permalink / raw)
To: Johannes Thumshirn; +Cc: wangyugui, trix, linux-btrfs
On Tue, Jan 25, 2022 at 08:30:34AM +0000, Johannes Thumshirn wrote:
> On Tue, 2022-01-25 at 13:04 +0800, Wang Yugui wrote:
> > Hi,
> >
> > Mabye we should enable '-Wmaybe-uninitialized' for btrfs 'make W=1'.
> >
> > There is another warning reproted by '-Wmaybe-uninitialized'
> > in btrfs misc-next.
> >
> > fs/btrfs/zoned.c:273:28: warning: ‘zno’ may be used uninitialized in
> > this function [-Wmaybe-uninitialized]
> > memcpy(zinfo->zone_cache + zno, zones,
> > ^
>
>
> Isn't that one a false positive?
>
> u32 zno;
>
> [...]
> /* Check cache */
> if (zinfo->zone_cache) {
> unsigned int i;
>
> ASSERT(IS_ALIGNED(pos, zinfo->zone_size));
> zno = pos >> zinfo->zone_size_shift;
> [...]
> }
>
> [...]
>
> /* Populate cache */
> if (zinfo->zone_cache)
> memcpy(zinfo->zone_cache + zno, zones,
> sizeof(*zinfo->zone_cache) * *nr_zones);
>
Yeah looks like a false positive, maybe it can't reason that
zinfo->zone_cache won't change between the conditions from NULL to valid
pointer.
And as there are other warnings in sb_zone_number we can't set
-Wmaybe-uninitialized by default. I think this could be even more
problematic with older compiler versions.
^ permalink raw reply [flat|nested] 7+ messages in thread