linux-kernel - [PATCH] staging: vc04_services: Fix RCU dereference check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211229153243.6064-1-treasure4paddy@gmail.com>
Date:   Wed, 29 Dec 2021 16:32:40 +0100
From:   Padmanabha Srinivasaiah <treasure4paddy@...il.com>
To:     linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Cc:     gregkh@...uxfoundation.org, nsaenz@...nel.org,
        treasure4paddy@...il.com, Stefan Wahren <stefan.wahren@...e.com>,
        Gaston Gonzalez <gascoar@...il.com>,
        Ojaswin Mujoo <ojaswin98@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        Phil Elwell <phil@...pberrypi.com>,
        bcm-kernel-feedback-list@...adcom.com
Subject: [PATCH] staging: vc04_services: Fix RCU dereference check

In service_callback path RCU dereference done without
rcu_read_[lock/unlock] pair, fixing same by using them.

[   32.201659] =============================
[   32.201664] WARNING: suspicious RCU usage
[   32.201670] 5.15.11-rt24-v8+ #3 Not tainted
[   32.201680] -----------------------------
[   32.201685] drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h:529 suspicious rcu_dereference_check() usage!
[   32.201695]
[   32.201695] other info that might help us debug this:
[   32.201695]
[   32.201700]
[   32.201700] rcu_scheduler_active = 2, debug_locks = 1
[   32.201708] no locks held by vchiq-slot/0/98.
[   32.201715]
[   32.201715] stack backtrace:
[   32.201723] CPU: 1 PID: 98 Comm: vchiq-slot/0 Not tainted 5.15.11-rt24-v8+ #3
[   32.201733] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[   32.201739] Call trace:
[   32.201742]  dump_backtrace+0x0/0x1b8
[   32.201772]  show_stack+0x20/0x30
[   32.201784]  dump_stack_lvl+0x8c/0xb8
[   32.201799]  dump_stack+0x18/0x34
[   32.201808]  lockdep_rcu_suspicious+0xe4/0xf8
[   32.201817]  service_callback+0x124/0x400
[   32.201830]  slot_handler_func+0xf60/0x1e20
[   32.201839]  kthread+0x19c/0x1a8
[   32.201849]  ret_from_fork+0x10/0x20

Signed-off-by: Padmanabha Srinivasaiah <treasure4paddy@...il.com>
---
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 6759a6261500..ee1b48db9681 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -1058,7 +1058,10 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header,
 
 	DEBUG_TRACE(SERVICE_CALLBACK_LINE);
 
+	rcu_read_lock();
 	service = handle_to_service(handle);
+	rcu_read_unlock();
+
 	if (WARN_ON(!service))
 		return VCHIQ_SUCCESS;
 
-- 
2.17.1