linux-kernel - [PATCH] i3c: Remove redundant lock in i3c_device

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: <20241029020950.31053-1-defa.li@mediatek.com>
Date: Tue, 29 Oct 2024 10:09:40 +0800
From: mtk25126 <defa.li@...iatek.com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>, Matthias Brugger
	<matthias.bgg@...il.com>, AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>
CC: <linux-i3c@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-mediatek@...ts.infradead.org>,
	<wsd_upstream@...iatek.com>, <mingchang.jia@...iatek.com>,
	<yuhan.wei@...iatek.com>, <hao.lin@...iatek.com>, mtk25126
	<defa.li@...iatek.com>
Subject: [PATCH] i3c: Remove redundant lock in i3c_device_uevent

We encountered the following lockdep warning.
The i3c_master_register function recursively acquires &i3cbus->lock twice,
which may cause a deadlock. 

Remove the logic of obtaining i3cbus->lock when using the i3c_device_uevent
function to obtain the i3c_device_info structure.

============================================
WARNING: possible recursive locking detected
6.11.0-mainline
--------------------------------------------
init/1 is trying to acquire lock:
f1ffff80a6a40dc0 (&i3cbus->lock){++++}-{3:3}, at: i3c_bus_normaluse_lock

but task is already holding lock:
f1ffff80a6a40dc0 (&i3cbus->lock){++++}-{3:3}, at: i3c_master_register

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&i3cbus->lock);
  lock(&i3cbus->lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by init/1:
 #0: fcffff809b6798f8 (&dev->mutex){....}-{3:3}, at: __driver_attach
 #1: f1ffff80a6a40dc0 (&i3cbus->lock){++++}-{3:3}, at: i3c_master_register

stack backtrace:
CPU: 6 UID: 0 PID: 1 Comm: init
Call trace:
 dump_backtrace+0xfc/0x17c
 show_stack+0x18/0x28
 dump_stack_lvl+0x40/0xc0
 dump_stack+0x18/0x24
 print_deadlock_bug+0x388/0x390
 __lock_acquire+0x18bc/0x32ec
 lock_acquire+0x134/0x2b0
 down_read+0x50/0x19c
 i3c_bus_normaluse_lock+0x14/0x24
 i3c_device_get_info+0x24/0x58
 i3c_device_uevent+0x34/0xa4
 dev_uevent+0x310/0x384
 kobject_uevent_env+0x244/0x414
 kobject_uevent+0x14/0x20
 device_add+0x278/0x460
 device_register+0x20/0x34
 i3c_master_register_new_i3c_devs+0x78/0x154
 i3c_master_register+0x6a0/0x6d4
 mtk_i3c_master_probe+0x3b8/0x4d8
 platform_probe+0xa0/0xe0
 really_probe+0x114/0x454
 __driver_probe_device+0xa0/0x15c
 driver_probe_device+0x3c/0x1ac
 __driver_attach+0xc4/0x1f0
 bus_for_each_dev+0x104/0x160
 driver_attach+0x24/0x34
 bus_add_driver+0x14c/0x294
 driver_register+0x68/0x104
 __platform_driver_register+0x20/0x30
 init_module+0x20/0xfe4
 do_one_initcall+0x184/0x464
 do_init_module+0x58/0x1ec
 load_module+0xefc/0x10c8
 __arm64_sys_finit_module+0x238/0x33c
 invoke_syscall+0x58/0x10c
 el0_svc_common+0xa8/0xdc
 do_el0_svc+0x1c/0x28
 el0_svc+0x50/0xac
 el0t_64_sync_handler+0x70/0xbc
 el0t_64_sync+0x1a8/0x1ac

Signed-off-by: mtk25126 <defa.li@...iatek.com>
---
 drivers/i3c/master.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 6f3eb710a75d..bb8a8bf0c4c7 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -282,7 +282,8 @@ static int i3c_device_uevent(const struct device *dev, struct kobj_uevent_env *e
 	struct i3c_device_info devinfo;
 	u16 manuf, part, ext;
 
-	i3c_device_get_info(i3cdev, &devinfo);
+	if (i3cdev->desc)
+		devinfo = i3cdev->desc->info;
 	manuf = I3C_PID_MANUF_ID(devinfo.pid);
 	part = I3C_PID_PART_ID(devinfo.pid);
 	ext = I3C_PID_EXTRA_INFO(devinfo.pid);
-- 
2.46.0