Recently the following failure has been observed on some vmcores when
using the mount command:
crash> mount
MOUNT SUPERBLK TYPE DEVNAME DIRNAME
ffff97a4818a3480 ffff979500013800 rootfs none /
ffff97e4846ca700 ffff97e484653000 sysfs sysfs /sys
...
ffff97b484753420 0 mount: invalid kernel virtual address: 0 type: "super_block buffer"
The kernel virtual address of the super_block is zero when the mount
command fails at the address 0xffff97b484753420. And the remaining
dumping information will be discarded. That is not expected.
Check the address and skip it with a warning, if this is an invalid
kernel virtual address, that can avoid truncating the remaining mount
dumps.
Reported-by: Dave Wysochanski <dwysocha@xxxxxxxxxx>
Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
---
filesys.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/filesys.c b/filesys.c
index c2ea78de821d..d64b54a9b822 100644
--- a/filesys.c
+++ b/filesys.c
@@ -1491,6 +1491,10 @@ show_mounts(ulong one_vfsmount, int flags, struct task_context *namespace_contex
}
sbp = ULONG(vfsmount_buf + OFFSET(vfsmount_mnt_sb));
+ if (!IS_KVADDR(sbp)) {
+ error(WARNING, "cannot get super_block from vfsmnt: 0x%lx\n", *vfsmnt);
+ continue;
+ }
if (flags)
fprintf(fp, "%s", mount_hdr);
--
2.37.1
--
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