perf/core: Fix PERF_RECORD_MMAP2 prot/flags for anonymous memory

Andres reported that MMAP2 records for anonymous memory always have
their protection field 0.

Turns out, someone daft put the prot/flags generation code in the file
branch, leaving them unset for anonymous memory.

Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Don Zickus <dzickus@redhat.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: anton@ozlabs.org
Cc: namhyung@kernel.org
Cc: stable@vger.kernel.org # v3.16+
Fixes: f972eb63b100 ("perf: Pass protection and flags bits through mmap2 interface")
Link: http://lkml.kernel.org/r/20170126221508.GF6536@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4e1f4c0070ceb48d231d20ff6776246c56e6aa74..e5aaa806702de888b63a82bdcb72766f7a317563 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6632,6 +6632,27 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
        char *buf = NULL;
        char *name;
 
+       if (vma->vm_flags & VM_READ)
+               prot |= PROT_READ;
+       if (vma->vm_flags & VM_WRITE)
+               prot |= PROT_WRITE;
+       if (vma->vm_flags & VM_EXEC)
+               prot |= PROT_EXEC;
+
+       if (vma->vm_flags & VM_MAYSHARE)
+               flags = MAP_SHARED;
+       else
+               flags = MAP_PRIVATE;
+
+       if (vma->vm_flags & VM_DENYWRITE)
+               flags |= MAP_DENYWRITE;
+       if (vma->vm_flags & VM_MAYEXEC)
+               flags |= MAP_EXECUTABLE;
+       if (vma->vm_flags & VM_LOCKED)
+               flags |= MAP_LOCKED;
+       if (vma->vm_flags & VM_HUGETLB)
+               flags |= MAP_HUGETLB;
+
        if (file) {
                struct inode *inode;
                dev_t dev;
@@ -6658,27 +6679,6 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
                maj = MAJOR(dev);
                min = MINOR(dev);
 
-               if (vma->vm_flags & VM_READ)
-                       prot |= PROT_READ;
-               if (vma->vm_flags & VM_WRITE)
-                       prot |= PROT_WRITE;
-               if (vma->vm_flags & VM_EXEC)
-                       prot |= PROT_EXEC;
-
-               if (vma->vm_flags & VM_MAYSHARE)
-                       flags = MAP_SHARED;
-               else
-                       flags = MAP_PRIVATE;
-
-               if (vma->vm_flags & VM_DENYWRITE)
-                       flags |= MAP_DENYWRITE;
-               if (vma->vm_flags & VM_MAYEXEC)
-                       flags |= MAP_EXECUTABLE;
-               if (vma->vm_flags & VM_LOCKED)
-                       flags |= MAP_LOCKED;
-               if (vma->vm_flags & VM_HUGETLB)
-                       flags |= MAP_HUGETLB;
-
                goto got_name;
        } else {
                if (vma->vm_ops && vma->vm_ops->name) {