linux: __get_nprocs_sched: do not feed CPU_COUNT_S with garbage [BZ #28850]

Pass the actual number of bytes returned by the kernel.

Fixes: 33099d72e41c ("linux: Simplify get_nprocs")
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
(cherry picked from commit 97ba273b505763325efd802dc3a9562dbba79579)

diff --git a/NEWS b/NEWS
index b1aae94cfbc6d50c51e2d015fb50f949dd10f670..d1602051d10e13b63d64ddd7fb28202b7cf9ae5f 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,7 @@ Version 2.35.1
 
 The following bugs are resolved with this release:
 
+  [28850] linux: __get_nprocs_sched reads uninitialized memory from the stack
   [28853] libc: tst-spawn6 changes current foreground process group
     (breaks test isolation)
 

diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c
index 4798cc337ebdf82ac2d000878c33f00e9ead0c55..c98c8ce3d4e9b4b5ef3d709bc94184be7720d37b 100644 (file)
--- a/sysdeps/unix/sysv/linux/getsysstats.c
+++ b/sysdeps/unix/sysv/linux/getsysstats.c
@@ -44,7 +44,7 @@ __get_nprocs_sched (void)
   int r = INTERNAL_SYSCALL_CALL (sched_getaffinity, 0, cpu_bits_size,
                                 cpu_bits);
   if (r > 0)
-    return CPU_COUNT_S (cpu_bits_size, (cpu_set_t*) cpu_bits);
+    return CPU_COUNT_S (r, (cpu_set_t*) cpu_bits);
   else if (r == -EINVAL)
     /* The input buffer is still not enough to store the number of cpus.  This
        is an arbitrary values assuming such systems should be rare and there