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authorArtem Fetishev <artem_fetishev@epam.com>2014-03-10 15:49:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-03-10 17:26:20 -0700
commit70335abb2689c8cd5df91bf2d95a65649addf50b (patch)
tree8f1c133a62d164f86d1f763668a98f6916262a93
parent2af120bc040c5ebcda156df6be6a66610ab6957f (diff)
downloadlinux-70335abb2689c8cd5df91bf2d95a65649addf50b.tar.gz
fs/proc/base.c: fix GPF in /proc/$PID/map_files
The expected logic of proc_map_files_get_link() is either to return 0 and initialize 'path' or return an error and leave 'path' uninitialized. By the time dname_to_vma_addr() returns 0 the corresponding vma may have already be gone. In this case the path is not initialized but the return value is still 0. This results in 'general protection fault' inside d_path(). Steps to reproduce: CONFIG_CHECKPOINT_RESTORE=y fd = open(...); while (1) { mmap(fd, ...); munmap(fd, ...); } ls -la /proc/$PID/map_files Addresses https://bugzilla.kernel.org/show_bug.cgi?id=68991 Signed-off-by: Artem Fetishev <artem_fetishev@epam.com> Signed-off-by: Aleksandr Terekhov <aleksandr_terekhov@epam.com> Reported-by: <wiebittewas@gmail.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/base.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 51507065263b..b9760628e1fd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1824,6 +1824,7 @@ static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
if (rc)
goto out_mmput;
+ rc = -ENOENT;
down_read(&mm->mmap_sem);
vma = find_exact_vma(mm, vm_start, vm_end);
if (vma && vma->vm_file) {