The 'icc_bw_lock' mutex is introduced in commit af42269c35
("interconnect: Fix locking for runpm vs reclaim") in order to decouple
serialization of bw aggregation from codepaths that require memory
allocation.
However commit d30f83d278 ("interconnect: core: Add dynamic id
allocation support") added a devm_kasprintf() call into a path protected
by the 'icc_bw_lock' which causes the following lockdep warning on
machines like the Lenovo ThinkPad X13s:
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc3 #15 Not tainted
------------------------------------------------------
(udev-worker)/342 is trying to acquire lock:
ffffb973f7ec4638 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_node_track_caller_noprof+0xa0/0x3e0
but task is already holding lock:
ffffb973f7f7f0e8 (icc_bw_lock){+.+.}-{4:4}, at: icc_node_add+0x44/0x154
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (icc_bw_lock){+.+.}-{4:4}:
icc_init+0x48/0x108
do_one_initcall+0x64/0x30c
kernel_init_freeable+0x27c/0x500
kernel_init+0x20/0x1d8
ret_from_fork+0x10/0x20
-> #0 (fs_reclaim){+.+.}-{0:0}:
__lock_acquire+0x136c/0x2114
lock_acquire+0x1c8/0x354
fs_reclaim_acquire+0x74/0xa8
__kmalloc_node_track_caller_noprof+0xa0/0x3e0
devm_kmalloc+0x54/0x124
devm_kvasprintf+0x74/0xd4
devm_kasprintf+0x58/0x80
icc_node_add+0xb4/0x154
qcom_osm_l3_probe+0x20c/0x314 [icc_osm_l3]
platform_probe+0x68/0xd8
really_probe+0xc0/0x38c
__driver_probe_device+0x7c/0x160
driver_probe_device+0x40/0x110
__driver_attach+0xfc/0x208
bus_for_each_dev+0x74/0xd0
driver_attach+0x24/0x30
bus_add_driver+0x110/0x234
driver_register+0x60/0x128
__platform_driver_register+0x24/0x30
osm_l3_driver_init+0x20/0x1000 [icc_osm_l3]
do_one_initcall+0x64/0x30c
do_init_module+0x58/0x23c
load_module+0x1df8/0x1f70
init_module_from_file+0x88/0xc4
idempotent_init_module+0x188/0x280
__arm64_sys_finit_module+0x6c/0xd8
invoke_syscall+0x48/0x110
el0_svc_common.constprop.0+0xc0/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x4c/0x158
el0t_64_sync_handler+0xc8/0xcc
el0t_64_sync+0x198/0x19c
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(icc_bw_lock);
lock(fs_reclaim);
lock(icc_bw_lock);
lock(fs_reclaim);
*** DEADLOCK ***
The icc_node_add() functions is not designed to fail, and as such it
should not do any memory allocation. In order to avoid this, add a new
helper function for the name generation to be called by drivers which
are using the new dynamic id feature.
Fixes: d30f83d278 ("interconnect: core: Add dynamic id allocation support")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Link: https://lore.kernel.org/r/20250625-icc-bw-lockdep-v3-1-2b8f8b8987c4@gmail.com
Co-developed-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20250627075854.26943-1-johan+linaro@kernel.org
Signed-off-by: Georgi Djakov <djakov@kernel.org>
c5b6059288