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authorAaro Koskinen <aaro.koskinen@nokia.com>2011-03-23 16:42:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-23 19:46:36 -0700
commit0db0c01b53a1a421513f91573241aabafb87802a (patch)
treebeb48c1fe733509945d6cfda2f830ebe3104aa02
parent51e031496d50f87ff519a63cfd4fc2f415f03336 (diff)
procfs: fix /proc/<pid>/maps heap check
The current code fails to print the "[heap]" marking if the heap is split into multiple mappings. Fix the check so that the marking is displayed in all possible cases: 1. vma matches exactly the heap 2. the heap vma is merged e.g. with bss 3. the heap vma is splitted e.g. due to locked pages Test cases. In all cases, the process should have mapping(s) with [heap] marking: (1) vma matches exactly the heap #include <stdio.h> #include <unistd.h> #include <sys/types.h> int main (void) { if (sbrk(4096) != (void *)-1) { printf("check /proc/%d/maps\n", (int)getpid()); while (1) sleep(1); } return 0; } # ./test1 check /proc/553/maps [1] + Stopped ./test1 # cat /proc/553/maps | head -4 00008000-00009000 r-xp 00000000 01:00 3113640 /test1 00010000-00011000 rw-p 00000000 01:00 3113640 /test1 00011000-00012000 rw-p 00000000 00:00 0 [heap] 4006f000-40070000 rw-p 00000000 00:00 0 (2) the heap vma is merged #include <stdio.h> #include <unistd.h> #include <sys/types.h> char foo[4096] = "foo"; char bar[4096]; int main (void) { if (sbrk(4096) != (void *)-1) { printf("check /proc/%d/maps\n", (int)getpid()); while (1) sleep(1); } return 0; } # ./test2 check /proc/556/maps [2] + Stopped ./test2 # cat /proc/556/maps | head -4 00008000-00009000 r-xp 00000000 01:00 3116312 /test2 00010000-00012000 rw-p 00000000 01:00 3116312 /test2 00012000-00014000 rw-p 00000000 00:00 0 [heap] 4004a000-4004b000 rw-p 00000000 00:00 0 (3) the heap vma is splitted (this fails without the patch) #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <sys/types.h> int main (void) { if ((sbrk(4096) != (void *)-1) && !mlockall(MCL_FUTURE) && (sbrk(4096) != (void *)-1)) { printf("check /proc/%d/maps\n", (int)getpid()); while (1) sleep(1); } return 0; } # ./test3 check /proc/559/maps [1] + Stopped ./test3 # cat /proc/559/maps|head -4 00008000-00009000 r-xp 00000000 01:00 3119108 /test3 00010000-00011000 rw-p 00000000 01:00 3119108 /test3 00011000-00012000 rw-p 00000000 00:00 0 [heap] 00012000-00013000 rw-p 00000000 00:00 0 [heap] It looks like the bug has been there forever, and since it only results in some information missing from a procfile, it does not fulfil the -stable "critical issue" criteria. Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/task_mmu.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 93381aae9363..636f1a1fdf87 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -251,8 +251,8 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
const char *name = arch_vma_name(vma);
if (!name) {
if (mm) {
- if (vma->vm_start <= mm->start_brk &&
- vma->vm_end >= mm->brk) {
+ if (vma->vm_start <= mm->brk &&
+ vma->vm_end >= mm->start_brk) {
name = "[heap]";
} else if (vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack) {