[Crash-utility] [PATCH] Fix "mount" command failure on Linux 6.8-rc1 and later
Kernel commit 2eea9ce4310d ("mounts: keep list of mounts in an rbtree")
changed the structure that keeps the list of mounts to an rbtree.
Without the patch, "mount" command fails with the following error:
crash> mount
mount: invalid structure member offset: mnt_namespace_list
FILE: filesys.c LINE: 1643 FUNCTION: get_mount_list()
Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
---
defs.h | 3 +++
filesys.c | 29 +++++++++++++++++++++++++++++
symbols.c | 3 +++
3 files changed, 35 insertions(+)
diff --git a/defs.h b/defs.h
index d1edce9893d1..ca1ac79ffa3e 100644
--- a/defs.h
+++ b/defs.h
@@ -2236,6 +2236,9 @@ struct offset_table { /* stash of commonly-used
offsets */
long zram_comp_algs;
long task_struct_thread_reg01;
long task_struct_thread_reg03;
+ long mnt_namespace_mounts;
+ long mnt_namespace_nr_mounts;
+ long mount_mnt_node;
};
struct size_table { /* stash of commonly-used sizes */
diff --git a/filesys.c b/filesys.c
index 1d0ee7f0b24a..81fe856699e1 100644
--- a/filesys.c
+++ b/filesys.c
@@ -1634,6 +1634,31 @@ get_mount_list(int *cntptr, struct task_context
*namespace_context)
&mnt_ns, sizeof(void *), "nsproxy mnt_ns",
RETURN_ON_ERROR|QUIET))
error(FATAL, "cannot determine mount list location!\n");
+
+ /* Linux 6.8 and later keep list of mounts in an rbtree. */
+ if (VALID_MEMBER(mnt_namespace_nr_mounts)) {
+ uint nr_mounts;
+ ulong *mntlist, *l;
+ struct rb_root *mounts;
+ struct rb_node *node;
+
+ readmem(mnt_ns + OFFSET(mnt_namespace_nr_mounts), KVADDR, &nr_mounts,
+ sizeof(uint), "mnt_namespace.nr_mounts", FAULT_ON_ERROR);
+
+ if (!nr_mounts)
+ error(FATAL, "nr_mounts is zero!\n");
+
+ mounts = (struct rb_root *)(mnt_ns + OFFSET(mnt_namespace_mounts));
+
+ mntlist = (ulong *)GETBUF(sizeof(ulong) * nr_mounts);
+ l = mntlist;
+ for (node = rb_first(mounts); node; l++, node = rb_next(node))
+ *l = (ulong)node - OFFSET(mount_mnt_node);
+
+ *cntptr = nr_mounts;
+ return mntlist;
+ }
+
if (!readmem(mnt_ns + OFFSET(mnt_namespace_root), KVADDR,
&root, sizeof(void *), "mnt_namespace root",
RETURN_ON_ERROR|QUIET))
@@ -2063,6 +2088,10 @@ vfs_init(void)
MEMBER_OFFSET_INIT(nsproxy_mnt_ns, "nsproxy", "mnt_ns");
MEMBER_OFFSET_INIT(mnt_namespace_root, "mnt_namespace",
"root");
MEMBER_OFFSET_INIT(mnt_namespace_list, "mnt_namespace",
"list");
+ /* Linux 6.8 and later */
+ MEMBER_OFFSET_INIT(mnt_namespace_mounts, "mnt_namespace",
"mounts");
+ MEMBER_OFFSET_INIT(mnt_namespace_nr_mounts, "mnt_namespace",
"nr_mounts");
+ MEMBER_OFFSET_INIT(mount_mnt_node, "mount", "mnt_node");
} else if (THIS_KERNEL_VERSION >= LINUX(2,4,20)) {
if (CRASHDEBUG(2))
fprintf(fp, "hardwiring namespace stuff\n");
diff --git a/symbols.c b/symbols.c
index d43785d3126a..b07b101767c8 100644
--- a/symbols.c
+++ b/symbols.c
@@ -9925,6 +9925,8 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(mnt_namespace_root));
fprintf(fp, " mnt_namespace_list: %ld\n",
OFFSET(mnt_namespace_list));
+ fprintf(fp, " mnt_namespace_mounts: %ld\n",
OFFSET(mnt_namespace_mounts));
+ fprintf(fp, " mnt_namespace_nr_mounts: %ld\n",
OFFSET(mnt_namespace_nr_mounts));
fprintf(fp, " pid_namespace_idr: %ld\n",
OFFSET(pid_namespace_idr));
@@ -10581,6 +10583,7 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(mount_mnt_devname));
fprintf(fp, " mount_mnt: %ld\n",
OFFSET(mount_mnt));
+ fprintf(fp, " mount_mnt_node: %ld\n", OFFSET(mount_mnt_node));
fprintf(fp, " namespace_root: %ld\n",
OFFSET(namespace_root));
fprintf(fp, " namespace_list: %ld\n",
--
2.31.1