From 0289ada4a31661016a0611a41a4886bb958e9985 Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Mon, 9 Feb 2026 12:44:33 +0000 Subject: coresight: Fix memory leak in coresight_alloc_device_name() 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: 0f5f9b6ba9e1 ("coresight: Use platform agnostic names") Reviewed-by: James Clark Signed-off-by: Leo Yan Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20260209-arm_coresight_refactor_dev_register-v4-1-62d6042f76f7@arm.com --- include/linux/coresight.h | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 2b48be97fcd0..2131febebee9 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -306,24 +306,19 @@ struct coresight_device { * coresight_dev_list - Mapping for devices to "name" index for device * names. * + * @node: Node on the global device index list. * @nr_idx: Number of entries already allocated. * @pfx: Prefix pattern for device name. * @fwnode_list: Array of fwnode_handles associated with each allocated * index, upto nr_idx entries. */ struct coresight_dev_list { + struct list_head node; int nr_idx; - const char *pfx; + char *pfx; struct fwnode_handle **fwnode_list; }; -#define DEFINE_CORESIGHT_DEVLIST(var, dev_pfx) \ -static struct coresight_dev_list (var) = { \ - .pfx = dev_pfx, \ - .nr_idx = 0, \ - .fwnode_list = NULL, \ -} - #define to_coresight_device(d) container_of(d, struct coresight_device, dev) /** @@ -663,8 +658,7 @@ void coresight_clear_self_claim_tag(struct csdev_access *csa); void coresight_clear_self_claim_tag_unlocked(struct csdev_access *csa); void coresight_disclaim_device(struct coresight_device *csdev); void coresight_disclaim_device_unlocked(struct coresight_device *csdev); -char *coresight_alloc_device_name(struct coresight_dev_list *devs, - struct device *dev); +char *coresight_alloc_device_name(const char *prefix, struct device *dev); bool coresight_loses_context_with_cpu(struct device *dev); -- cgit v1.2.3