[Crash-utility] Re: [PATCH] Fix "kmem -i" and "swap" commands on Linux 6.10-rc1 and later kernels

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. Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; --- NOTE: This patch can be applied on top of my '[PATCH] Fix "kmem -v" option on Linux 6.9 and later kernels' patch. Otherwise, please adjust the hunk for offset_table. 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 95de33188070..64bf785b7a1b 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..28f901f16adf 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 283b98a8fbfe..0bf050ab62d0 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", -- 2.31.1 -- Crash-utility mailing list -- devel(a)lists.crash-utility.osci.io To unsubscribe send an email to devel-leave(a)lists.crash-utility.osci.io https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ Contribution Guidelines: https://github.com/crash-utility/crash/wiki