[Crash-utility] Re: [PATCH] Fix get_pathname() not handling stacked mounts
Should read "mount | grep tmpfs" (and not "grep /tmp/test"):
crash> mount | grep tmpfs
ffff9648e7febc00 ffff9648d91ac800 tmpfs tmpfs /tmp/test
ffff9648c9281380 ffff9648d91ac800 tmpfs tmpfs /tmp/test/
ffff9648c8e9a700 ffff9648d91ac800 tmpfs tmpfs /
|-----Original Message-----
|From: Aureau, Georges (Kernel Tools ERT)
|Sent: Tuesday, September 23, 2025 10:08 AM
|To: devel(a)lists.crash-utility.osci.io
|Subject: [PATCH] Fix get_pathname() not handling stacked mounts
|
|[PATCH] Fix get_pathname() not handling stacked mounts
|
|This get_pathname() issue can be duplicated as follow:
|
|sudo mkdir -p /tmp/test
|sudo mount -t tmpfs tmpfs /tmp/test
|sudo mount --make-private /tmp/test
|sudo mount --bind /tmp/test /tmp/test
|sudo mount --bind /tmp/test /tmp/test
|sudo mount -o remount,ro /tmp/test
|
|$ sudo crash /usr/lib/debug/boot/vmlinux-$(uname -r)
|crash> mount | grep /tmp/test
|ffff9648e7febc00 ffff9648d91ac800 tmpfs tmpfs /tmp/test
|ffff9648c9281380 ffff9648d91ac800 tmpfs tmpfs /tmp/test/
|ffff9648c8e9a700 ffff9648d91ac800 tmpfs tmpfs /
|
|The last mount is not printed properly, and this is impacting diagnostic
|when looking at vmcore from complex containers mount environments.
|
|Signed-off-by: Georges Aureau <georges.aureau(a)hpe.com>
|--
|diff --git a/filesys.c b/filesys.c
|index 8d13807..af6d616 100644
|--- a/filesys.c
|+++ b/filesys.c
|@@ -3140,6 +3154,7 @@ get_pathname(ulong dentry, char *pathname, int
|length, int full, ulong vfsmnt)
| tmp_vfsmnt = vfsmnt;
|
| do {
|+ more_vfsmnt:
| tmp_dentry = parent;
|
| dentry_buf = fill_dentry_cache(tmp_dentry);
|@@ -3195,6 +3210,7 @@ get_pathname(ulong dentry, char *pathname, int
|length, int full, ulong vfsmnt)
| break;
| else
| tmp_vfsmnt = mnt_parent;
|+ goto more_vfsmnt;
| }
| } else if (VALID_STRUCT(mount)) {
| if (tmp_vfsmnt) {
|@@ -3213,6 +3229,7 @@ get_pathname(ulong dentry, char *pathname, int
|length, int full, ulong vfsmnt)
| break;
| else
| tmp_vfsmnt = mnt_parent +
|OFFSET(mount_mnt);
|+ goto more_vfsmnt;
| }
| }
| else {
|@@ -3222,6 +3239,9 @@ get_pathname(ulong dentry, char *pathname, int
|length, int full, ulong vfsmnt)
| }
|
| } while (tmp_dentry != parent && parent);
|+ if (!STREQ(pathname, "/") && LASTCHAR(pathname) == '/') {
|+ LASTCHAR(pathname) = '\0';
|+ }
|
| if (mnt_buf)
| FREEBUF(mnt_buf);