[Crash-utility] [PATCH 2/v2] Fix "mount" MNT_CURSOR (kernels 5.8-6.7)
[PATCH 2/v2] Fix "mount" MNT_CURSOR (kernels 5.8-6.7):
Fix "mount" MNT_CURSOR entries (kernels 5.8-6.7):
crash> mount > mount.out
WARNING: cannot get super_block from vfsmnt: 0xff35d65eb1cc1820
crash> struct mount.mnt.mnt_sb,mnt.mnt_flags -x 0xff35d65eb1cc1820
mnt.mnt_sb = 0x0,
mnt.mnt_flags = 0x10000000,
When crashing with running "findmnt" commands, the mount list will
have entries with mnt.mnt_flags==MNT_CURSOR (and mnt.mnt_sb==NULL).
Such entries should be skipped without errors.
Signed-off-by: Georges Aureau <georges.aureau(a)hpe.com>
--
defs.h | 2 ++
filesys.c | 15 +++++++++++++++
symbols.c | 4 ++++
3 files changed, 21 insertions(+)
diff --git a/defs.h b/defs.h
index 156ac02..3fd7d89 100644
--- a/defs.h
+++ b/defs.h
@@ -2274,6 +2274,8 @@ struct offset_table { /* stash of commonly-used
offsets */
long request_queue_tag_set;
long blk_mq_tag_set_flags;
long blk_mq_tag_set_shared_tags;
+ long vfsmount_mnt_flags;
+ long proc_mounts_cursor;
};
struct size_table { /* stash of commonly-used sizes */
diff --git a/filesys.c b/filesys.c
index 8d13807..1f8803d 100644
--- a/filesys.c
+++ b/filesys.c
@@ -1367,6 +1367,10 @@ cmd_mount(void)
close_tmpfile();
}
+/* For kernels 5.8-6.7, we're skipping show mount cursor entries.
+ */
+#define MNT_CURSOR 0x10000000
+
/*
* Do the work for cmd_mount();
*/
@@ -1492,6 +1496,15 @@ show_mounts(ulong one_vfsmount, int flags, struct task_context
*namespace_contex
sbp = ULONG(vfsmount_buf + OFFSET(vfsmount_mnt_sb));
if (!IS_KVADDR(sbp)) {
+ if (sbp == 0 && VALID_MEMBER(proc_mounts_cursor)
&&
+ VALID_MEMBER(vfsmount_mnt_flags)) {
+ int mnt_flags = INT(vfsmount_buf +
OFFSET(vfsmount_mnt_flags));
+ if (mnt_flags == MNT_CURSOR) {
+ if (CRASHDEBUG(1))
+ fprintf(stderr,"skipped cursor
vfsmnt: 0x%lx\n", *vfsmnt);
+ continue;
+ }
+ }
error(WARNING, "cannot get super_block from vfsmnt:
0x%lx\n", *vfsmnt);
continue;
}
@@ -2081,6 +2094,8 @@ vfs_init(void)
if (INVALID_MEMBER(vfsmount_mnt_devname))
MEMBER_OFFSET_INIT(mount_mnt_mountpoint,
"mount", "mnt_mountpoint");
+ MEMBER_OFFSET_INIT(vfsmount_mnt_flags, "vfsmount",
"mnt_flags");
+ MEMBER_OFFSET_INIT(proc_mounts_cursor, "proc_mounts",
"cursor");
MEMBER_OFFSET_INIT(mount_mnt, "mount", "mnt");
MEMBER_OFFSET_INIT(namespace_root, "namespace", "root");
MEMBER_OFFSET_INIT(task_struct_nsproxy, "task_struct",
"nsproxy");
diff --git a/symbols.c b/symbols.c
index 112bcc6..fd91c2e 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10691,6 +10691,10 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(vfsmount_mnt_mountpoint));
fprintf(fp, " vfsmount_mnt_parent: %ld\n",
OFFSET(vfsmount_mnt_parent));
+ fprintf(fp, " vfsmount_mnt_flags: %ld\n",
+ OFFSET(vfsmount_mnt_flags));
+ fprintf(fp, " proc_mounts_cursor: %ld\n",
+ OFFSET(proc_mounts_cursor));
fprintf(fp, " mount_mnt_parent: %ld\n",
OFFSET(mount_mnt_parent));
fprintf(fp, " mount_mnt_mountpoint: %ld\n",