On Wed, Jun 12, 2024 at 2:08 PM <devel-requ...@lists.crash-utility.osci.io> wrote:
> Date: Wed, 12 Jun 2024 06:06:35 +0000 > From: HAGIO KAZUHITO(萩尾 一仁) <k-hagio...@nec.com> > Subject: [Crash-utility] Re: PATCH] Fix "kmem -i" and "swap" commands > on Linux 6.10-rc1 and later kernels > To: lijiang <liji...@redhat.com>, "devel@lists.crash-utility.osci.io" > <devel@lists.crash-utility.osci.io> > Message-ID: <2db40a61-d404-4733-a62a-6068f2911...@nec.com> > Content-Type: text/plain; charset="utf-8" > > On 2024/06/12 13:55, lijiang wrote: > > Thank you for the fix, Kazu. > > > > On Tue, Jun 11, 2024 at 10:42 AM < > devel-requ...@lists.crash-utility.osci.io <mailto: > devel-requ...@lists.crash-utility.osci.io>> wrote: > > > > Date: Tue, 11 Jun 2024 02:40:55 +0000 > > From: HAGIO KAZUHITO(萩尾 一仁) <k-hagio...@nec.com <mailto: > k-hagio...@nec.com>> > > Subject: [Crash-utility] [PATCH] Fix "kmem -i" and "swap" commands on > > Linux 6.10-rc1 and later kernels > > To: "devel@lists.crash-utility.osci.io <mailto: > devel@lists.crash-utility.osci.io>" > > <devel@lists.crash-utility.osci.io <mailto: > devel@lists.crash-utility.osci.io>> > > Message-ID: <1718073652-13444-1-git-send-email-k-hagio...@nec.com > <mailto:1718073652-13444-1-git-send-email-k-hagio...@nec.com>> > > Content-Type: text/plain; charset="iso-2022-jp" > > > > 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...@nec.com <mailto: > k-hagio...@nec.com>> > > --- > > 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"); > > > > > > This patch looks good, but I still have one question: > > The 'swap_file' has been added into the struct swap_info_struct since > linux v2.6.12-rc2, > > and until now it(its type) has been never changed, it indicates that the > above checking is always true. > > > > STREQ(MEMBER_TYPE_NAME("swap_info_struct", "swap_file"), "file") > > > > Is that expected behavior? Just want to confirm with you. > > Yes. > Thank you for the confirmation, and explanation below, Kazu. As far as I checked, swap_file was changed from 'dentry *' to 'file *' > at somewhere between v2.4.0 and v2.6.0, so not always true. > > Seems no full history in linux github. I checked it from the linux initial git repo: commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (tag: v2.6.12-rc2) Author: Linus Torvalds <torva...@ppc970.osdl.org> Date: Sat Apr 16 15:20:36 2005 -0700 Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! get_pathname()'s first arg is dentry, we have to choose the else-if block > without old_block_size, so I decided to use its type information directly > > } else if > (VALID_MEMBER(swap_info_struct_old_block_size) || > swap_file_is_file) { > > The other if / else blocks are for very old kernels, so maybe they won't > be used, but if we don't remove these, I think this is a reasonable way. > > Sounds good to me. > Does this answer your question? > Yes. Thank you, Kazu. I have no other issues. For the patch: Ack. Thanks Lianbo > > Thanks, > Kazu > > > > > Thanks > > Lianbo > > > > 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 > > >
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