From 5feddda9ac7ea72eac3d5a83251fa023b67aebce Mon Sep 17 00:00:00 2001 From: Jonathan Rajotte Date: Thu, 4 Apr 2019 21:47:41 +0000 Subject: lttng-ust: backport musl workaround musl implementation for _SC_NPROCESSORS_CONF is a bit fishy. [1] https://www.openwall.com/lists/musl/2019/03/15/5 Anyway, we implemented a fallback. This patch should be gone by next recipe update. Signed-off-by: Jonathan Rajotte Signed-off-by: Richard Purdie --- ...-around-broken-_SC_NPROCESSORS_CONF-on-MU.patch | 109 +++++++++++++++++++++ meta/recipes-kernel/lttng/lttng-ust_2.10.3.bb | 2 + 2 files changed, 111 insertions(+) create mode 100644 meta/recipes-kernel/lttng/lttng-ust/0001-compat-work-around-broken-_SC_NPROCESSORS_CONF-on-MU.patch diff --git a/meta/recipes-kernel/lttng/lttng-ust/0001-compat-work-around-broken-_SC_NPROCESSORS_CONF-on-MU.patch b/meta/recipes-kernel/lttng/lttng-ust/0001-compat-work-around-broken-_SC_NPROCESSORS_CONF-on-MU.patch new file mode 100644 index 0000000000..5c4bd36726 --- /dev/null +++ b/meta/recipes-kernel/lttng/lttng-ust/0001-compat-work-around-broken-_SC_NPROCESSORS_CONF-on-MU.patch @@ -0,0 +1,109 @@ +From 5de7c318804a7b1edce8562d4891b4c74aac0677 Mon Sep 17 00:00:00 2001 +From: Michael Jeanson +Date: Wed, 20 Mar 2019 11:07:35 -0400 +Subject: [PATCH] compat: work around broken _SC_NPROCESSORS_CONF on MUSL libc + +On MUSL libc the _SC_NPROCESSORS_CONF sysconf will report the number of +CPUs allocated to the task based on the affinity mask instead of the +total number of CPUs configured on the system. + +Upstream-Status: Accepted [1] [5de7c318804a7b1edce8562d4891b4c74aac0677] +[1] https://lists.lttng.org/pipermail/lttng-dev/2019-March/028616.html + +Signed-off-by: Michael Jeanson +Signed-off-by: Mathieu Desnoyers +--- + libringbuffer/smp.c | 66 +++++++++++++++++++++++++++++++++++++++++++++ + 1 file changed, 66 insertions(+) + +diff --git a/libringbuffer/smp.c b/libringbuffer/smp.c +index 9e7114be..656a75da 100644 +--- a/libringbuffer/smp.c ++++ b/libringbuffer/smp.c +@@ -2,6 +2,7 @@ + * libringbuffer/smp.c + * + * Copyright (C) 2011-2012 Mathieu Desnoyers ++ * Copyright (C) 2019 Michael Jeanson + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public +@@ -26,6 +27,7 @@ + + int __num_possible_cpus; + ++#if (defined(__GLIBC__) || defined( __UCLIBC__)) + void _get_num_possible_cpus(void) + { + int result; +@@ -43,3 +45,67 @@ void _get_num_possible_cpus(void) + return; + __num_possible_cpus = result; + } ++ ++#else ++ ++/* ++ * The MUSL libc implementation of the _SC_NPROCESSORS_CONF sysconf does not ++ * return the number of configured CPUs in the system but relies on the cpu ++ * affinity mask of the current task. ++ * ++ * So instead we use a strategy similar to GLIBC's, counting the cpu ++ * directories in "/sys/devices/system/cpu" and fallback on the value from ++ * sysconf if it fails. ++ */ ++ ++#include ++#include ++#include ++#include ++#include ++ ++#define __max(a,b) ((a)>(b)?(a):(b)) ++ ++void _get_num_possible_cpus(void) ++{ ++ int result, count = 0; ++ DIR *cpudir; ++ struct dirent *entry; ++ ++ cpudir = opendir("/sys/devices/system/cpu"); ++ if (cpudir == NULL) ++ goto end; ++ ++ /* ++ * Count the number of directories named "cpu" followed by and ++ * integer. This is the same strategy as glibc uses. ++ */ ++ while ((entry = readdir(cpudir))) { ++ if (entry->d_type == DT_DIR && ++ strncmp(entry->d_name, "cpu", 3) == 0) { ++ ++ char *endptr; ++ unsigned long cpu_num; ++ ++ cpu_num = strtoul(entry->d_name + 3, &endptr, 10); ++ if ((cpu_num < ULONG_MAX) && (endptr != entry->d_name + 3) ++ && (*endptr == '\0')) { ++ count++; ++ } ++ } ++ } ++ ++end: ++ /* ++ * Get the sysconf value as a fallback. Keep the highest number. ++ */ ++ result = __max(sysconf(_SC_NPROCESSORS_CONF), count); ++ ++ /* ++ * If both methods failed, don't store the value. ++ */ ++ if (result < 1) ++ return; ++ __num_possible_cpus = result; ++} ++#endif +-- +2.17.1 + diff --git a/meta/recipes-kernel/lttng/lttng-ust_2.10.3.bb b/meta/recipes-kernel/lttng/lttng-ust_2.10.3.bb index c0f408eeec..d546104129 100644 --- a/meta/recipes-kernel/lttng/lttng-ust_2.10.3.bb +++ b/meta/recipes-kernel/lttng/lttng-ust_2.10.3.bb @@ -27,7 +27,9 @@ PE = "2" SRC_URI = "https://lttng.org/files/lttng-ust/lttng-ust-${PV}.tar.bz2 \ file://lttng-ust-doc-examples-disable.patch \ + file://0001-compat-work-around-broken-_SC_NPROCESSORS_CONF-on-MU.patch \ " + SRC_URI[md5sum] = "ffcfa8c1ba9a52f002d240e936e9afa2" SRC_URI[sha256sum] = "9e8420f90d5f963f7aa32bc6d44adc1e491136f687c69ffb7a3075d33b40852b" -- cgit 1.2.3-korg