From 561fa844777c1bd9c0c6937be272e6ea73ff94f6 Mon Sep 17 00:00:00 2001 From: Kostya Kortchinsky Date: Mon, 20 Jan 2020 09:50:22 -0800 Subject: [PATCH] [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 --- compiler-rt/lib/scudo/standalone/common.h | 1 + compiler-rt/lib/scudo/standalone/linux.cpp | 5 ++++- compiler-rt/lib/scudo/standalone/tsd_shared.h | 4 +++- 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/compiler-rt/lib/scudo/standalone/common.h b/compiler-rt/lib/scudo/standalone/common.h index a700eb5..e026e34 100644 --- a/compiler-rt/lib/scudo/standalone/common.h +++ b/compiler-rt/lib/scudo/standalone/common.h @@ -126,6 +126,7 @@ inline uptr getPageSizeCached() { return getPageSizeSlow(); } +// Returns 0 if the number of CPUs could not be determined. u32 getNumberOfCPUs(); const char *getEnv(const char *Name); diff --git a/compiler-rt/lib/scudo/standalone/linux.cpp b/compiler-rt/lib/scudo/standalone/linux.cpp index 3c12084..3b75628 100644 --- a/compiler-rt/lib/scudo/standalone/linux.cpp +++ b/compiler-rt/lib/scudo/standalone/linux.cpp @@ -132,7 +132,10 @@ u64 getMonotonicTime() { 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(CPU_COUNT(&CPUs)); } diff --git a/compiler-rt/lib/scudo/standalone/tsd_shared.h b/compiler-rt/lib/scudo/standalone/tsd_shared.h index 5ab8269..1626732 100644 --- a/compiler-rt/lib/scudo/standalone/tsd_shared.h +++ b/compiler-rt/lib/scudo/standalone/tsd_shared.h @@ -18,7 +18,9 @@ template struct TSDRegistrySharedT { 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 *>( map(nullptr, sizeof(TSD) * NumberOfTSDs, "scudo:tsd")); for (u32 I = 0; I < NumberOfTSDs; I++) -- 2.7.4