[PATCH] btrfs: zoned: fix missing rcu locking in error message when loading zone info

[PATCH] btrfs: zoned: fix missing rcu locking in error message when loading zone info

[fdmanana]

From: Filipe Manana <fdmanana@suse.com>

At btrfs_load_zone_info() we have an error path that is dereferecing the
name of a device which is a RCU string but we are not holding a RCU read
lock, which is incorrect.

Fix this by using btrfs_err_in_rcu() instead of btrfs_err().

The problem is there since commit 08e11a3db098 ("btrfs: zoned: load zone's
allocation offset"), back then at btrfs_load_block_group_zone_info() but
then later on that code was factored out into the helper
btrfs_load_zone_info() by commit 09a46725cc84 ("btrfs: zoned: factor out
per-zone logic from btrfs_load_block_group_zone_info").

Fixes: 08e11a3db098 ("btrfs: zoned: load zone's allocation offset")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/zoned.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 00a016691d8e..dbcbf754d284 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1340,7 +1340,7 @@ static int btrfs_load_zone_info(struct btrfs_fs_info *fs_info, int zone_idx,
 	switch (zone.cond) {
 	case BLK_ZONE_COND_OFFLINE:
 	case BLK_ZONE_COND_READONLY:
-		btrfs_err(fs_info,
+		btrfs_err_in_rcu(fs_info,
 		"zoned: offline/readonly zone %llu on device %s (devid %llu)",
 			  (info->physical >> device->zone_info->zone_size_shift),
 			  rcu_str_deref(device->name), device->devid);
-- 
2.43.0

Re: [PATCH] btrfs: zoned: fix missing rcu locking in error message when loading zone info

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH] btrfs: zoned: fix missing rcu locking in error message when loading zone info

[Qu Wenruo]

在 2024/10/2 23:45, fdmanana@kernel.org 写道:
> From: Filipe Manana <fdmanana@suse.com>
>
> At btrfs_load_zone_info() we have an error path that is dereferecing the
> name of a device which is a RCU string but we are not holding a RCU read
> lock, which is incorrect.
>
> Fix this by using btrfs_err_in_rcu() instead of btrfs_err().
>
> The problem is there since commit 08e11a3db098 ("btrfs: zoned: load zone's
> allocation offset"), back then at btrfs_load_block_group_zone_info() but
> then later on that code was factored out into the helper
> btrfs_load_zone_info() by commit 09a46725cc84 ("btrfs: zoned: factor out
> per-zone logic from btrfs_load_block_group_zone_info").
>
> Fixes: 08e11a3db098 ("btrfs: zoned: load zone's allocation offset")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/zoned.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 00a016691d8e..dbcbf754d284 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -1340,7 +1340,7 @@ static int btrfs_load_zone_info(struct btrfs_fs_info *fs_info, int zone_idx,
>   	switch (zone.cond) {
>   	case BLK_ZONE_COND_OFFLINE:
>   	case BLK_ZONE_COND_READONLY:
> -		btrfs_err(fs_info,
> +		btrfs_err_in_rcu(fs_info,
>   		"zoned: offline/readonly zone %llu on device %s (devid %llu)",
>   			  (info->physical >> device->zone_info->zone_size_shift),
>   			  rcu_str_deref(device->name), device->devid);

Re: [PATCH] btrfs: zoned: fix missing rcu locking in error message when loading zone info

[Naohiro Aota]

On Wed, Oct 02, 2024 at 03:15:07PM GMT, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> At btrfs_load_zone_info() we have an error path that is dereferecing the
> name of a device which is a RCU string but we are not holding a RCU read
> lock, which is incorrect.
> 
> Fix this by using btrfs_err_in_rcu() instead of btrfs_err().
> 
> The problem is there since commit 08e11a3db098 ("btrfs: zoned: load zone's
> allocation offset"), back then at btrfs_load_block_group_zone_info() but
> then later on that code was factored out into the helper
> btrfs_load_zone_info() by commit 09a46725cc84 ("btrfs: zoned: factor out
> per-zone logic from btrfs_load_block_group_zone_info").
> 
> Fixes: 08e11a3db098 ("btrfs: zoned: load zone's allocation offset")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Thank you catching this.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>

> ---
>  fs/btrfs/zoned.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 00a016691d8e..dbcbf754d284 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -1340,7 +1340,7 @@ static int btrfs_load_zone_info(struct btrfs_fs_info *fs_info, int zone_idx,
>  	switch (zone.cond) {
>  	case BLK_ZONE_COND_OFFLINE:
>  	case BLK_ZONE_COND_READONLY:
> -		btrfs_err(fs_info,
> +		btrfs_err_in_rcu(fs_info,
>  		"zoned: offline/readonly zone %llu on device %s (devid %llu)",
>  			  (info->physical >> device->zone_info->zone_size_shift),
>  			  rcu_str_deref(device->name), device->devid);
> -- 
> 2.43.0
>