From: Jiri Olsa Date: Tue, 14 Mar 2017 14:20:53 +0000 (+0100) Subject: x86/intel_rdt: Put group node in rdtgroup_kn_unlock X-Git-Tag: v4.10.5~7 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=343146100991fbdf4d637c035f95b4b06a870c82;p=thirdparty%2Fkernel%2Fstable.git x86/intel_rdt: Put group node in rdtgroup_kn_unlock commit 49ec8f5b6ae3ab60385492cad900ffc8a523c895 upstream. The rdtgroup_kn_unlock waits for the last user to release and put its node. But it's calling kernfs_put on the node which calls the rdtgroup_kn_unlock, which might not be the group's directory node, but another group's file node. This race could be easily reproduced by running 2 instances of following script: mount -t resctrl resctrl /sys/fs/resctrl/ pushd /sys/fs/resctrl/ mkdir krava echo "krava" > krava/schemata rmdir krava popd umount /sys/fs/resctrl It triggers the slub debug error message with following command line config: slub_debug=,kernfs_node_cache. Call kernfs_put on the group's node to fix it. Fixes: 60cf5e101fd4 ("x86/intel_rdt: Add mkdir to resctrl file system") Signed-off-by: Jiri Olsa Cc: Fenghua Yu Cc: Peter Zijlstra Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Shaohua Li Link: http://lkml.kernel.org/r/1489501253-20248-1-git-send-email-jolsa@kernel.org Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 8af04afdfcb96..84c0f23ea644b 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -727,7 +727,7 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn) if (atomic_dec_and_test(&rdtgrp->waitcount) && (rdtgrp->flags & RDT_DELETED)) { kernfs_unbreak_active_protection(kn); - kernfs_put(kn); + kernfs_put(rdtgrp->kn); kfree(rdtgrp); } else { kernfs_unbreak_active_protection(kn);