From: Guenter Roeck Date: Thu, 16 Oct 2025 18:49:17 +0000 (-0500) Subject: ipmi: Fix handling of messages with provided receive message pointer X-Git-Tag: v6.12.54~22 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=04610b77809f6d579e8b90561027fa683755c331;p=thirdparty%2Fkernel%2Fstable.git ipmi: Fix handling of messages with provided receive message pointer commit e2c69490dda5d4c9f1bfbb2898989c8f3530e354 upstream Prior to commit b52da4054ee0 ("ipmi: Rework user message limit handling"), i_ipmi_request() used to increase the user reference counter if the receive message is provided by the caller of IPMI API functions. This is no longer the case. However, ipmi_free_recv_msg() is still called and decreases the reference counter. This results in the reference counter reaching zero, the user data pointer is released, and all kinds of interesting crashes are seen. Fix the problem by increasing user reference counter if the receive message has been provided by the caller. Fixes: b52da4054ee0 ("ipmi: Rework user message limit handling") Reported-by: Eric Dumazet Cc: Eric Dumazet Cc: Greg Thelen Signed-off-by: Guenter Roeck Message-ID: <20251006201857.3433837-1-linux@roeck-us.net> Signed-off-by: Corey Minyard Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index 6fb8210879bbb..99fe013219712 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -2311,8 +2311,11 @@ static int i_ipmi_request(struct ipmi_user *user, if (supplied_recv) { recv_msg = supplied_recv; recv_msg->user = user; - if (user) + if (user) { atomic_inc(&user->nr_msgs); + /* The put happens when the message is freed. */ + kref_get(&user->refcount); + } } else { recv_msg = ipmi_alloc_recv_msg(user); if (IS_ERR(recv_msg))