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0289ada4a3
The memory leak detector reports:
echo clear > /sys/kernel/debug/kmemleak
modprobe coresight_funnel
rmmod coresight_funnel
# Scan memory leak and report it
echo scan > /sys/kernel/debug/kmemleak
cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff0008020c7200 (size 64):
comm "modprobe", pid 410, jiffies 4295333721
hex dump (first 32 bytes):
d8 da fe 7e 09 00 ff ff e8 2e ff 7e 09 00 ff ff ...~.......~....
b0 6c ff 7e 09 00 ff ff 30 83 00 7f 09 00 ff ff .l.~....0.......
backtrace (crc 4116a690):
kmemleak_alloc+0xd8/0xf8
__kmalloc_node_track_caller_noprof+0x2c8/0x6f0
krealloc_node_align_noprof+0x13c/0x2c8
coresight_alloc_device_name+0xe4/0x158 [coresight]
0xffffd327ecef8394
0xffffd327ecef85ec
amba_probe+0x118/0x1c8
really_probe+0xc8/0x3f0
__driver_probe_device+0x88/0x190
driver_probe_device+0x44/0x120
__driver_attach+0x100/0x238
bus_for_each_dev+0x84/0xf0
driver_attach+0x2c/0x40
bus_add_driver+0x128/0x258
driver_register+0x64/0x138
__amba_driver_register+0x2c/0x48
The memory leak is caused by not freeing the device list that maintains
device indices.
This device list preserves stable device indices across unbind and
rebind device operations, so it does not share the same lifetime as a
device instances and must only be freed when the module is unloaded.
Some modules do not implement a module exit callback because they are
registered using module_platform_driver(). As a result, the device
list cannot be released during module exit for those modules.
Fix this by moving the device list into the core layer. As a general
solution, instead of maintaining a static list in each driver, drivers
now allocate device lists via coresight_allocate_device_list() and
device indices via coresight_allocate_device_idx().
The list is released only when the core module is unloaded by calling
coresight_release_device_list(), avoiding the leak.
Fixes: 0f5f9b6ba9 ("coresight: Use platform agnostic names")
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260209-arm_coresight_refactor_dev_register-v4-1-62d6042f76f7@arm.com