4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 52eb74339a6233c69f4e3794b69ea7c98eeeae1b ]
rdt_find_domain() returns an ERR_PTR() that is generated from a provided domain id when the value is negative.
Care needs to be taken when creating an ERR_PTR() from this value because a subsequent check using IS_ERR() expects the error to be within the MAX_ERRNO range. Using an invalid domain id as an ERR_PTR() does work at this time since this is currently always -1. Using this undocumented assumption is fragile since future users of rdt_find_domain() may not be aware of thus assumption.
Two related issues are addressed:
- Ensure that rdt_find_domain() always returns a valid error value by forcing the error to be -ENODEV when a negative domain id is provided.
- In a few instances the return value of rdt_find_domain() is just checked for NULL - fix these to include a check of ERR_PTR.
Fixes: d89b7379015f ("x86/intel_rdt/cqm: Add mon_data") Fixes: 521348b011d6 ("x86/intel_rdt: Introduce utility to obtain CDP peer") Signed-off-by: Reinette Chatre reinette.chatre@intel.com Signed-off-by: Borislav Petkov bp@suse.de Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Tony Luck tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: x86-ml x86@kernel.org Link: https://lkml.kernel.org/r/b88cd4ff6a75995bf8db9b0ea546908fe50f69f3.154447985... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/cpu/intel_rdt.c | 2 +- arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 2 +- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c index 44272b7107ad..2d0a565fd0bb 100644 --- a/arch/x86/kernel/cpu/intel_rdt.c +++ b/arch/x86/kernel/cpu/intel_rdt.c @@ -421,7 +421,7 @@ struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id, struct list_head *l;
if (id < 0) - return ERR_PTR(id); + return ERR_PTR(-ENODEV);
list_for_each(l, &r->domains) { d = list_entry(l, struct rdt_domain, list); diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c index efa4a519f5e5..c8b72aff55e0 100644 --- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c +++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c @@ -467,7 +467,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
r = &rdt_resources_all[resid]; d = rdt_find_domain(r, domid, NULL); - if (!d) { + if (IS_ERR_OR_NULL(d)) { ret = -ENOENT; goto out; } diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index f27b8115ffa2..951c61367688 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -1029,7 +1029,7 @@ static int rdt_cdp_peer_get(struct rdt_resource *r, struct rdt_domain *d, * peer RDT CDP resource. Hence the WARN. */ _d_cdp = rdt_find_domain(_r_cdp, d->id, NULL); - if (WARN_ON(!_d_cdp)) { + if (WARN_ON(IS_ERR_OR_NULL(_d_cdp))) { _r_cdp = NULL; ret = -EINVAL; }