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authorTejun Heo <tj@kernel.org>2017-02-09 01:30:56 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-09 02:41:43 +0300
commit4d59b6ccf000862beed6fc0765d3209f98a8d8a2 (patch)
tree598294e81b74149a78ebed29b3a9ce6c53b1e1e1 /include
parent0911d0041c22922228ca52a977d7b0b0159fee4b (diff)
downloadlinux-4d59b6ccf000862beed6fc0765d3209f98a8d8a2.tar.xz
cpumask: use nr_cpumask_bits for parsing functions
Commit 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") converted both cpumask printing and parsing functions to use nr_cpu_ids instead of nr_cpumask_bits. While this was okay for the printing functions as it just picked one of the two output formats that we were alternating between depending on a kernel config, doing the same for parsing wasn't okay. nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS. We can always use nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can be more efficient to use NR_CPUS when we can get away with it. Converting the printing functions to nr_cpu_ids makes sense because it affects how the masks get presented to userspace and doesn't break anything; however, using nr_cpu_ids for parsing functions can incorrectly leave the higher bits uninitialized while reading in these masks from userland. As all testing and comparison functions use nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks can erroneously yield false negative results. This made the taskstats interface incorrectly return -EINVAL even when the inputs were correct. Fix it by restoring the parse functions to use nr_cpumask_bits instead of nr_cpu_ids. Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de> Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/cpumask.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index c717f5ea88cb..b3d2c1a89ac4 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -560,7 +560,7 @@ static inline void cpumask_copy(struct cpumask *dstp,
static inline int cpumask_parse_user(const char __user *buf, int len,
struct cpumask *dstp)
{
- return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpu_ids);
+ return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
}
/**
@@ -575,7 +575,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len,
struct cpumask *dstp)
{
return bitmap_parselist_user(buf, len, cpumask_bits(dstp),
- nr_cpu_ids);
+ nr_cpumask_bits);
}
/**
@@ -590,7 +590,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
char *nl = strchr(buf, '\n');
unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf);
- return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpu_ids);
+ return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
}
/**
@@ -602,7 +602,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
*/
static inline int cpulist_parse(const char *buf, struct cpumask *dstp)
{
- return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpu_ids);
+ return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpumask_bits);
}
/**