[scudo][standalone] Allow sched_getaffinity to fail
Summary:
In some configuration, `sched_getaffinity` can fail. Some reasons for
that being the lack of `CAP_SYS_NICE` capability or some syscall
filtering and so on.
This should not be fatal to the allocator, so in this situation, we
will fallback to the `MaxTSDCount` value specified in the allocator
configuration.
Reviewers: cferris, eugenis, hctim, morehouse, pcc
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73055
GitOrigin-RevId: 561fa844777c1bd9c0c6937be272e6ea73ff94f6
diff --git a/common.h b/common.h
index a700eb5..e026e34 100644
--- a/common.h
+++ b/common.h
@@ -126,6 +126,7 @@
return getPageSizeSlow();
}
+// Returns 0 if the number of CPUs could not be determined.
u32 getNumberOfCPUs();
const char *getEnv(const char *Name);
diff --git a/linux.cpp b/linux.cpp
index 3c12084..3b75628 100644
--- a/linux.cpp
+++ b/linux.cpp
@@ -132,7 +132,10 @@
u32 getNumberOfCPUs() {
cpu_set_t CPUs;
- CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
+ // sched_getaffinity can fail for a variety of legitimate reasons (lack of
+ // CAP_SYS_NICE, syscall filtering, etc), in which case we shall return 0.
+ if (sched_getaffinity(0, sizeof(cpu_set_t), &CPUs) != 0)
+ return 0;
return static_cast<u32>(CPU_COUNT(&CPUs));
}
diff --git a/tsd_shared.h b/tsd_shared.h
index 5ab8269..1626732 100644
--- a/tsd_shared.h
+++ b/tsd_shared.h
@@ -18,7 +18,9 @@
void initLinkerInitialized(Allocator *Instance) {
Instance->initLinkerInitialized();
CHECK_EQ(pthread_key_create(&PThreadKey, nullptr), 0); // For non-TLS
- NumberOfTSDs = Min(Max(1U, getNumberOfCPUs()), MaxTSDCount);
+ const u32 NumberOfCPUs = getNumberOfCPUs();
+ NumberOfTSDs =
+ (NumberOfCPUs == 0) ? MaxTSDCount : Min(NumberOfCPUs, MaxTSDCount);
TSDs = reinterpret_cast<TSD<Allocator> *>(
map(nullptr, sizeof(TSD<Allocator>) * NumberOfTSDs, "scudo:tsd"));
for (u32 I = 0; I < NumberOfTSDs; I++)
