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| author | Rakib Mullick <rakib.mullick@gmail.com> | 2017-10-23 19:01:54 +0600 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-10-24 11:47:25 +0200 |
| commit | e22cdc3fc5991956146b9856d36b4971fe54dcd6 (patch) | |
| tree | 788b7cab5afd4e592a08577f2670b4f6c845e9a0 /kernel/sched | |
| parent | 6be53520ad8f87dc748f381e4e8e6a846a4b466b (diff) | |
| download | linux-e22cdc3fc5991956146b9856d36b4971fe54dcd6.tar.gz linux-e22cdc3fc5991956146b9856d36b4971fe54dcd6.tar.bz2 linux-e22cdc3fc5991956146b9856d36b4971fe54dcd6.zip | |
sched/isolcpus: Fix "isolcpus=" boot parameter handling when !CONFIG_CPUMASK_OFFSTACK
cpulist_parse() uses nr_cpumask_bits as a limit to parse the
passed buffer from kernel commandline. What nr_cpumask_bits
represents varies depending upon the CONFIG_CPUMASK_OFFSTACK option:
- If CONFIG_CPUMASK_OFFSTACK=n, then nr_cpumask_bits is the same as
NR_CPUS, which might not represent the # of CPUs that really exist
(default 64). So, there's a chance of a gap between nr_cpu_ids
and NR_CPUS, which ultimately lead towards invalid cpulist_parse()
operation. For example, if isolcpus=9 is passed on an 8 cpu
system (CONFIG_CPUMASK_OFFSTACK=n) it doesn't show the error
that it's supposed to.
This patch fixes this bug by finding the last CPU of the passed
isolcpus= list and checking it against nr_cpu_ids.
It also fixes the error message where the nr_cpu_ids should be
nr_cpu_ids-1, since CPU numbering starts from 0.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adobriyan@gmail.com
Cc: akpm@linux-foundation.org
Cc: longman@redhat.com
Cc: mka@chromium.org
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/20171023130154.9050-1-rakib.mullick@gmail.com
[ Enhanced the changelog and the kernel message. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
include/linux/cpumask.h | 16 ++++++++++++++++
kernel/sched/topology.c | 4 ++--
2 files changed, 18 insertions(+), 2 deletions(-)
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/topology.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index e50450c2fed8..e3d31b0880dc 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -476,8 +476,8 @@ static int __init isolated_cpu_setup(char *str) alloc_bootmem_cpumask_var(&cpu_isolated_map); ret = cpulist_parse(str, cpu_isolated_map); - if (ret) { - pr_err("sched: Error, all isolcpus= values must be between 0 and %u\n", nr_cpu_ids); + if (ret || cpumask_last(cpu_isolated_map) >= nr_cpu_ids) { + pr_err("sched: Error, all isolcpus= values must be between 0 and %u - ignoring them.\n", nr_cpu_ids-1); return 0; } return 1; |