diff mbox series

[net,v2] devlink: Hold devlink lock on health reporter dump get

Message ID 1696510216-189379-1-git-send-email-moshe@nvidia.com (mailing list archive)
State Accepted
Commit aba0e909dc20eceb1de985474af459f82e7b0b82
Delegated to: Netdev Maintainers
Headers show
Series [net,v2] devlink: Hold devlink lock on health reporter dump get | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1342 this patch: 1342
netdev/cc_maintainers warning 2 maintainers not CCed: edumazet@google.com pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 1364 this patch: 1364
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1365 this patch: 1365
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 96 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Moshe Shemesh Oct. 5, 2023, 12:50 p.m. UTC 
Devlink health dump get callback should take devlink lock as any other
devlink callback. Otherwise, since devlink_mutex was removed, this
callback is not protected from a race of the reporter being destroyed
while handling the callback.

Add devlink lock to the callback and to any call for
devlink_health_do_dump(). This should be safe as non of the drivers dump
callback implementation takes devlink lock.

As devlink lock is added to any callback of dump, the reporter dump_lock
is now redundant and can be removed.

Fixes: d3efc2a6a6d8 ("net: devlink: remove devlink_mutex")
Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
---
v1->v2:
- Commit message, added why this fix is necessary and why its safe to do.
---
 net/devlink/health.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

Comments

Przemek Kitszel Oct. 5, 2023, 1:33 p.m. UTC | #1 
On 10/5/23 14:50, Moshe Shemesh wrote:
> Devlink health dump get callback should take devlink lock as any other
> devlink callback. Otherwise, since devlink_mutex was removed, this
> callback is not protected from a race of the reporter being destroyed
> while handling the callback.
> 
> Add devlink lock to the callback and to any call for
> devlink_health_do_dump(). This should be safe as non of the drivers dump
> callback implementation takes devlink lock.
> 
> As devlink lock is added to any callback of dump, the reporter dump_lock
> is now redundant and can be removed.
> 
> Fixes: d3efc2a6a6d8 ("net: devlink: remove devlink_mutex")
> Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
> ---
> v1->v2:
> - Commit message, added why this fix is necessary and why its safe to do.
> ---
>   net/devlink/health.c | 30 ++++++++++++++++--------------
>   1 file changed, 16 insertions(+), 14 deletions(-)
> 

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
patchwork-bot+netdevbpf@kernel.org Oct. 6, 2023, 11 p.m. UTC | #2 
Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 5 Oct 2023 15:50:16 +0300 you wrote:
> Devlink health dump get callback should take devlink lock as any other
> devlink callback. Otherwise, since devlink_mutex was removed, this
> callback is not protected from a race of the reporter being destroyed
> while handling the callback.
> 
> Add devlink lock to the callback and to any call for
> devlink_health_do_dump(). This should be safe as non of the drivers dump
> callback implementation takes devlink lock.
> 
> [...]

Here is the summary with links:
  - [net,v2] devlink: Hold devlink lock on health reporter dump get
    https://git.kernel.org/netdev/net/c/aba0e909dc20

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/devlink/health.c b/net/devlink/health.c
index 638cad8d5c65..51e6e81e31bb 100644
--- a/net/devlink/health.c
+++ b/net/devlink/health.c
@@ -58,7 +58,6 @@  struct devlink_health_reporter {
 	struct devlink *devlink;
 	struct devlink_port *devlink_port;
 	struct devlink_fmsg *dump_fmsg;
-	struct mutex dump_lock; /* lock parallel read/write from dump buffers */
 	u64 graceful_period;
 	bool auto_recover;
 	bool auto_dump;
@@ -125,7 +124,6 @@  __devlink_health_reporter_create(struct devlink *devlink,
 	reporter->graceful_period = graceful_period;
 	reporter->auto_recover = !!ops->recover;
 	reporter->auto_dump = !!ops->dump;
-	mutex_init(&reporter->dump_lock);
 	return reporter;
 }
 
@@ -226,7 +224,6 @@  EXPORT_SYMBOL_GPL(devlink_health_reporter_create);
 static void
 devlink_health_reporter_free(struct devlink_health_reporter *reporter)
 {
-	mutex_destroy(&reporter->dump_lock);
 	if (reporter->dump_fmsg)
 		devlink_fmsg_free(reporter->dump_fmsg);
 	kfree(reporter);
@@ -625,10 +622,10 @@  int devlink_health_report(struct devlink_health_reporter *reporter,
 	}
 
 	if (reporter->auto_dump) {
-		mutex_lock(&reporter->dump_lock);
+		devl_lock(devlink);
 		/* store current dump of current error, for later analysis */
 		devlink_health_do_dump(reporter, priv_ctx, NULL);
-		mutex_unlock(&reporter->dump_lock);
+		devl_unlock(devlink);
 	}
 
 	if (!reporter->auto_recover)
@@ -1262,7 +1259,7 @@  int devlink_nl_cmd_health_reporter_diagnose_doit(struct sk_buff *skb,
 }
 
 static struct devlink_health_reporter *
-devlink_health_reporter_get_from_cb(struct netlink_callback *cb)
+devlink_health_reporter_get_from_cb_lock(struct netlink_callback *cb)
 {
 	const struct genl_info *info = genl_info_dump(cb);
 	struct devlink_health_reporter *reporter;
@@ -1272,10 +1269,12 @@  devlink_health_reporter_get_from_cb(struct netlink_callback *cb)
 	devlink = devlink_get_from_attrs_lock(sock_net(cb->skb->sk), attrs);
 	if (IS_ERR(devlink))
 		return NULL;
-	devl_unlock(devlink);
 
 	reporter = devlink_health_reporter_get_from_attrs(devlink, attrs);
-	devlink_put(devlink);
+	if (!reporter) {
+		devl_unlock(devlink);
+		devlink_put(devlink);
+	}
 	return reporter;
 }
 
@@ -1284,16 +1283,20 @@  int devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb,
 {
 	struct devlink_nl_dump_state *state = devlink_dump_state(cb);
 	struct devlink_health_reporter *reporter;
+	struct devlink *devlink;
 	int err;
 
-	reporter = devlink_health_reporter_get_from_cb(cb);
+	reporter = devlink_health_reporter_get_from_cb_lock(cb);
 	if (!reporter)
 		return -EINVAL;
 
-	if (!reporter->ops->dump)
+	devlink = reporter->devlink;
+	if (!reporter->ops->dump) {
+		devl_unlock(devlink);
+		devlink_put(devlink);
 		return -EOPNOTSUPP;
+	}
 
-	mutex_lock(&reporter->dump_lock);
 	if (!state->idx) {
 		err = devlink_health_do_dump(reporter, NULL, cb->extack);
 		if (err)
@@ -1309,7 +1312,8 @@  int devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb,
 	err = devlink_fmsg_dumpit(reporter->dump_fmsg, skb, cb,
 				  DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET);
 unlock:
-	mutex_unlock(&reporter->dump_lock);
+	devl_unlock(devlink);
+	devlink_put(devlink);
 	return err;
 }
 
@@ -1326,9 +1330,7 @@  int devlink_nl_cmd_health_reporter_dump_clear_doit(struct sk_buff *skb,
 	if (!reporter->ops->dump)
 		return -EOPNOTSUPP;
 
-	mutex_lock(&reporter->dump_lock);
 	devlink_health_dump_clear(reporter);
-	mutex_unlock(&reporter->dump_lock);
 	return 0;
 }