Messages in this thread Patch in this message | | | From | Xiaochen Shen <> | Subject | [PATCH] x86/resctrl: Fix potential lockdep warning | Date | Thu, 7 Nov 2019 06:36:36 +0800 |
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rdtgroup_cpus_write() and mkdir_rdt_prepare() call rdtgroup_kn_lock_live() -> kernfs_to_rdtgroup() to get 'rdtgrp', and then call rdt_last_cmd_xxx() 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_xxx() will result in a lockdep warning.
Remove rdt_last_cmd_xxx() in these two paths. Just returning error should be sufficient to report to the user that the entry doesn't exist any more.
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> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> --- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 4 ---- 1 file changed, 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; } -- 1.8.3.1
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