| Message ID | 20221116094958.2141072-1-pierre.gondois@arm.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 2613cc29c5723881ca603b1a3b50f0107010d5d6 |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | [-next,v2] cacheinfo: Remove of_node_put() for fw_token | expand |
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 04317cde800c..950b22cdb5f7 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -317,8 +317,6 @@ static void cache_shared_cpu_map_remove(unsigned int cpu) cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map); cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map); } - if (of_have_populated_dt()) - of_node_put(this_leaf->fw_token); } }
fw_token is used for DT/ACPI systems to identify CPUs sharing caches. For DT based systems, fw_token is set to a pointer to a DT node. commit 3da72e18371c ("cacheinfo: Decrement refcount in cache_setup_of_node()") doesn't increment the refcount of fw_token anymore in cache_setup_of_node(). fw_token is indeed used as a token and not as a (struct device_node*), so no reference to fw_token should be kept. However, [1] is triggered when hotplugging a CPU multiple times since cache_shared_cpu_map_remove() decrements the refcount to fw_token at each CPU unplugging, eventually reaching 0. Remove of_node_put() for fw_token in cache_shared_cpu_map_remove(). [1] ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 4 PID: 32 at lib/refcount.c:22 refcount_warn_saturate (lib/refcount.c:22 (discriminator 3)) Modules linked in: CPU: 4 PID: 32 Comm: cpuhp/4 Tainted: G W 6.1.0-rc1-14091-g9fdf2ca7b9c8 #76 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Oct 31 2022 pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate (lib/refcount.c:22 (discriminator 3)) lr : refcount_warn_saturate (lib/refcount.c:22 (discriminator 3)) [...] Call trace: [...] of_node_release (drivers/of/dynamic.c:335) kobject_put (lib/kobject.c:677 lib/kobject.c:704 ./include/linux/kref.h:65 lib/kobject.c:721) of_node_put (drivers/of/dynamic.c:49) free_cache_attributes.part.0 (drivers/base/cacheinfo.c:712) cacheinfo_cpu_pre_down (drivers/base/cacheinfo.c:718) cpuhp_invoke_callback (kernel/cpu.c:247 (discriminator 4)) cpuhp_thread_fun (kernel/cpu.c:785) smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) kthread (kernel/kthread.c:376) ret_from_fork (arch/arm64/kernel/entry.S:861) ---[ end trace 0000000000000000 ]--- Fixes: 3da72e18371c ("cacheinfo: Decrement refcount in cache_setup_of_node()") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> --- Notes: v2: - Update commit message. [Sudeep] drivers/base/cacheinfo.c | 2 -- 1 file changed, 2 deletions(-)