From: Artem Fetishev <[email protected]>
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
https://jira.sw.ru/browse/PSBM-68472
Signed-off-by: Artem Fetishev <[email protected]>
Signed-off-by: Aleksandr Terekhov <[email protected]>
Reported-by: <[email protected]>
Acked-by: Pavel Emelyanov <[email protected]>
Acked-by: Cyrill Gorcunov <[email protected]>
Reviewed-by: "Eric W. Biederman" <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Stanislav Kinsburskiy <[email protected]>
---
fs/proc/base.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0af670c..291e503 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2028,6 +2028,7 @@ 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) {
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