This is a note to let you know that I've just added the patch titled
i3c: Use i3cdev->desc->info instead of calling i3c_device_get_info() to avoid deadlock
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i3c-use-i3cdev-desc-info-instead-of-calling-i3c_devi.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 230241e652c4b0cd3482b93ba12639c34f7656cc
Author: Defa Li <defa.li@xxxxxxxxxxxx>
Date: Thu Nov 7 21:25:39 2024 +0800
i3c: Use i3cdev->desc->info instead of calling i3c_device_get_info() to avoid deadlock
[ Upstream commit 6cf7b65f7029914dc0cd7db86fac9ee5159008c6 ]
A deadlock may happen since the i3c_master_register() acquires
&i3cbus->lock twice. See the log below.
Use i3cdev->desc->info instead of calling i3c_device_info() to
avoid acquiring the lock twice.
v2:
- Modified the title and commit message
============================================
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: Defa Li <defa.li@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20241107132549.25439-1-defa.li@xxxxxxxxxxxx
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 68170b1b32678..3f581a1cf8e62 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -257,7 +257,8 @@ static int i3c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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);
