linux-kernel - [PATCH 5.15 236/917] ipmi: Disable some operations during a panic

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Date:   Mon, 15 Nov 2021 17:55:31 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Corey Minyard <cminyard@...sta.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 236/917] ipmi: Disable some operations during a panic

From: Corey Minyard <cminyard@...sta.com>

[ Upstream commit b36eb5e7b75a756baa64909a176dd4269ee05a8b ]

Don't do kfree or other risky things when oops_in_progress is set.
It's easy enough to avoid doing them

Signed-off-by: Corey Minyard <cminyard@...sta.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/char/ipmi/ipmi_msghandler.c | 10 +++++++---
 drivers/char/ipmi/ipmi_watchdog.c   | 17 ++++++++++++-----
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index e96cb5c4f97a3..a08f53f208bfe 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -4789,7 +4789,9 @@ static atomic_t recv_msg_inuse_count = ATOMIC_INIT(0);
 static void free_smi_msg(struct ipmi_smi_msg *msg)
 {
 	atomic_dec(&smi_msg_inuse_count);
-	kfree(msg);
+	/* Try to keep as much stuff out of the panic path as possible. */
+	if (!oops_in_progress)
+		kfree(msg);
 }
 
 struct ipmi_smi_msg *ipmi_alloc_smi_msg(void)
@@ -4808,7 +4810,9 @@ EXPORT_SYMBOL(ipmi_alloc_smi_msg);
 static void free_recv_msg(struct ipmi_recv_msg *msg)
 {
 	atomic_dec(&recv_msg_inuse_count);
-	kfree(msg);
+	/* Try to keep as much stuff out of the panic path as possible. */
+	if (!oops_in_progress)
+		kfree(msg);
 }
 
 static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
@@ -4826,7 +4830,7 @@ static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
 
 void ipmi_free_recv_msg(struct ipmi_recv_msg *msg)
 {
-	if (msg->user)
+	if (msg->user && !oops_in_progress)
 		kref_put(&msg->user->refcount, free_user);
 	msg->done(msg);
 }
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index f855a9665c284..883b4a3410122 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -342,13 +342,17 @@ static atomic_t msg_tofree = ATOMIC_INIT(0);
 static DECLARE_COMPLETION(msg_wait);
 static void msg_free_smi(struct ipmi_smi_msg *msg)
 {
-	if (atomic_dec_and_test(&msg_tofree))
-		complete(&msg_wait);
+	if (atomic_dec_and_test(&msg_tofree)) {
+		if (!oops_in_progress)
+			complete(&msg_wait);
+	}
 }
 static void msg_free_recv(struct ipmi_recv_msg *msg)
 {
-	if (atomic_dec_and_test(&msg_tofree))
-		complete(&msg_wait);
+	if (atomic_dec_and_test(&msg_tofree)) {
+		if (!oops_in_progress)
+			complete(&msg_wait);
+	}
 }
 static struct ipmi_smi_msg smi_msg = {
 	.done = msg_free_smi
@@ -434,8 +438,10 @@ static int _ipmi_set_timeout(int do_heartbeat)
 	rv = __ipmi_set_timeout(&smi_msg,
 				&recv_msg,
 				&send_heartbeat_now);
-	if (rv)
+	if (rv) {
+		atomic_set(&msg_tofree, 0);
 		return rv;
+	}
 
 	wait_for_completion(&msg_wait);
 
@@ -580,6 +586,7 @@ restart:
 				      &recv_msg,
 				      1);
 	if (rv) {
+		atomic_set(&msg_tofree, 0);
 		pr_warn("heartbeat send failure: %d\n", rv);
 		return rv;
 	}
-- 
2.33.0