File 0008-Fix-kmem-i-and-swap-commands-on-Linux-6.10... of Package crash

Overview Repositories Revisions Requests Users Attributes Meta

File 0008-Fix-kmem-i-and-swap-commands-on-Linux-6.10-rc1-and-l.patch of Package crash (Revision d517f2688b6ca51eb5379394a164f987)

Currently displaying revision d517f2688b6ca51eb5379394a164f987 , Show latest

From: =?UTF-8?q?HAGIO=20KAZUHITO=28=E8=90=A9=E5=B0=BE=E3=80=80=E4=B8=80?=
 =?UTF-8?q?=E4=BB=81=29?= <k-hagio-ab@nec.com>
Date: Tue, 11 Jun 2024 02:40:55 +0000
Subject: Fix "kmem -i" and "swap" commands on Linux 6.10-rc1 and later kernels
Git-repo: https://github.com/crash-utility/crash.git
Git-commit: 3452fe802bf94d15879b3c5fd17c793a2b67a231
Patch-mainline: 8.0.6
References: bsc#1228388

Kernel commit 798cb7f9aec3 ("swapon(2)/swapoff(2): don't bother with
block size") removed swap_info_struct.old_block_size member at Linux
6.10-rc1.  The crash-utility has used this to determine whether a swap
is a partition or file and to determine the way to get the swap path.

Withtout the patch, the "kmem -i" and "swap" commands fail with the
following error messsage:

crash> kmem -i
  ...
     TOTAL HUGE  13179392      50.3 GB         ----
      HUGE FREE  13179392      50.3 GB  100% of TOTAL HUGE

swap: invalid (optional) structure member offsets: swap_info_struct_swap_device or swap_info_struct_old_block_size
        FILE: memory.c  LINE: 16032  FUNCTION: dump_swap_info()

The swap_file member of recent swap_info_struct is a pointer to a
struct file (once upon a time it was dentry), use this fact directly.

Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 defs.h    |  1 +
 filesys.c |  1 +
 memory.c  | 28 +++++++++++++++++++++++-----
 symbols.c |  1 +
 4 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/defs.h b/defs.h
index da856c08f11a..49e6923ede54 100644
--- a/defs.h
+++ b/defs.h
@@ -2242,6 +2242,7 @@ struct offset_table {                    /* stash of commonly-used offsets */
 	long log_caller_id;
 	long vmap_node_busy;
 	long rb_list_head;
+	long file_f_inode;
 };
 
 struct size_table {         /* stash of commonly-used sizes */
diff --git a/filesys.c b/filesys.c
index 81fe856699e1..406ebb299780 100644
--- a/filesys.c
+++ b/filesys.c
@@ -2038,6 +2038,7 @@ vfs_init(void)
 	MEMBER_OFFSET_INIT(file_f_dentry, "file", "f_dentry");
 	MEMBER_OFFSET_INIT(file_f_vfsmnt, "file", "f_vfsmnt");
 	MEMBER_OFFSET_INIT(file_f_count, "file", "f_count");
+	MEMBER_OFFSET_INIT(file_f_inode, "file", "f_inode");
 	MEMBER_OFFSET_INIT(path_mnt, "path", "mnt");
 	MEMBER_OFFSET_INIT(path_dentry, "path", "dentry");
 	if (INVALID_MEMBER(file_f_dentry)) {
diff --git a/memory.c b/memory.c
index acb8507cfb75..a74ebafe0ab5 100644
--- a/memory.c
+++ b/memory.c
@@ -16075,6 +16075,8 @@ dump_swap_info(ulong swapflags, ulong *totalswap_pages, ulong *totalused_pages)
 	char buf3[BUFSIZE];
 	char buf4[BUFSIZE];
 	char buf5[BUFSIZE];
+	int swap_file_is_file =
+		STREQ(MEMBER_TYPE_NAME("swap_info_struct", "swap_file"), "file");
 
 	if (!symbol_exists("nr_swapfiles"))
 		error(FATAL, "nr_swapfiles doesn't exist in this kernel!\n");
@@ -16118,9 +16120,21 @@ dump_swap_info(ulong swapflags, ulong *totalswap_pages, ulong *totalused_pages)
 		swap_file = ULONG(vt->swap_info_struct + 
 			OFFSET(swap_info_struct_swap_file));
 
-                swap_device = INT(vt->swap_info_struct +
-                        OFFSET_OPTION(swap_info_struct_swap_device, 
-			swap_info_struct_old_block_size));
+		/* Linux 6.10 and later */
+		if (INVALID_MEMBER(swap_info_struct_swap_device) &&
+		    INVALID_MEMBER(swap_info_struct_old_block_size) &&
+		    swap_file_is_file) {
+			ulong inode;
+			ushort mode;
+			readmem(swap_file + OFFSET(file_f_inode), KVADDR, &inode,
+				sizeof(ulong), "swap_file.f_inode", FAULT_ON_ERROR);
+			readmem(inode + OFFSET(inode_i_mode), KVADDR, &mode,
+				sizeof(ushort), "inode.i_mode", FAULT_ON_ERROR);
+			swap_device = S_ISBLK(mode);
+		} else
+			swap_device = INT(vt->swap_info_struct +
+				OFFSET_OPTION(swap_info_struct_swap_device,
+				swap_info_struct_old_block_size));
 
                 pages = INT(vt->swap_info_struct +
                         OFFSET(swap_info_struct_pages));
@@ -16161,8 +16175,12 @@ dump_swap_info(ulong swapflags, ulong *totalswap_pages, ulong *totalused_pages)
                         		OFFSET(swap_info_struct_swap_vfsmnt));
 				get_pathname(swap_file, buf, BUFSIZE, 
 					1, vfsmnt);
-			} else if (VALID_MEMBER
-				(swap_info_struct_old_block_size)) {
+			} else if (VALID_MEMBER(swap_info_struct_old_block_size) ||
+				    swap_file_is_file) {
+				/*
+				 * Linux 6.10 and later kernels do not have old_block_size,
+				 * but this still should work, if swap_file is file.
+				 */
 				devname = vfsmount_devname(file_to_vfsmnt(swap_file), 
 					buf1, BUFSIZE);
 				get_pathname(file_to_dentry(swap_file), 
diff --git a/symbols.c b/symbols.c
index f3c94b0a8588..69a1fbb2f071 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10522,6 +10522,7 @@ dump_offset_table(char *spec, ulong makestruct)
 		OFFSET(file_f_count));
         fprintf(fp, "                   file_f_path: %ld\n", 
 		OFFSET(file_f_path));
+        fprintf(fp, "                  file_f_inode: %ld\n", OFFSET(file_f_inode));
         fprintf(fp, "                      path_mnt: %ld\n", 
 		OFFSET(path_mnt));
         fprintf(fp, "                   path_dentry: %ld\n", 
-- 
2.45.2

Places

File 0008-Fix-kmem-i-and-swap-commands-on-Linux-6.10-rc1-and-l.patch of Package crash (Revision d517f2688b6ca51eb5379394a164f987)

Places