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authorXiaochen Shen <xiaochen.shen@intel.com>2019-11-07 01:36:36 +0300
committerBorislav Petkov <bp@suse.de>2019-11-13 14:34:44 +0300
commitc8eafe1495303bfd0eedaa8156b1ee9082ee9642 (patch)
treeed43632d17ddd199b8b67ce5b10bf8dcd9c80f49
parentfc5db58539b49351e76f19817ed1102bf7c712d0 (diff)
downloadlinux-c8eafe1495303bfd0eedaa8156b1ee9082ee9642.tar.xz
x86/resctrl: Fix potential lockdep warning
rdtgroup_cpus_write() and mkdir_rdt_prepare() call rdtgroup_kn_lock_live() -> kernfs_to_rdtgroup() to get 'rdtgrp', and then call the rdt_last_cmd_{clear,puts,...}() functions which will check if rdtgroup_mutex is held/requires its caller to hold rdtgroup_mutex. But if 'rdtgrp' returned from kernfs_to_rdtgroup() is NULL, rdtgroup_mutex is not held and calling rdt_last_cmd_{clear,puts,...}() will result in a self-incurred, potential lockdep warning. Remove the rdt_last_cmd_{clear,puts,...}() calls in these two paths. Just returning error should be sufficient to report to the user that the entry doesn't exist any more. [ bp: Massage. ] Fixes: 94457b36e8a5 ("x86/intel_rdt: Add diagnostics when writing the cpus file") Fixes: cfd0f34e4cd5 ("x86/intel_rdt: Add diagnostics when making directories") Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: pei.p.jia@intel.com Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/1573079796-11713-1-git-send-email-xiaochen.shen@intel.com
-rw-r--r--arch/x86/kernel/cpu/resctrl/rdtgroup.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index a46dee8e78db..2e3b06d6bbc6 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -461,10 +461,8 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
}
rdtgrp = rdtgroup_kn_lock_live(of->kn);
- rdt_last_cmd_clear();
if (!rdtgrp) {
ret = -ENOENT;
- rdt_last_cmd_puts("Directory was removed\n");
goto unlock;
}
@@ -2648,10 +2646,8 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
int ret;
prdtgrp = rdtgroup_kn_lock_live(prgrp_kn);
- rdt_last_cmd_clear();
if (!prdtgrp) {
ret = -ENODEV;
- rdt_last_cmd_puts("Directory was removed\n");
goto out_unlock;
}