Hi Tao

attached split 2 patches.

Thanks
Guanyou


Tao Liu <[email protected]> 于2025年12月5日周五 11:31写道:

> Hi Guanyou,
>
> On Fri, Dec 5, 2025 at 3:03 PM Guanyou Chen <[email protected]>
> wrote:
> >
> > Hi Tao,
> >
> > Check swap_file_is_file from crash commit 3452fe802bf94
> > ("Fix "kmem -i" and "swap" commands on Linux 6.10-rc1 and later kernels")
> >
> > Thanks,
> > Guanyou
> >
> > Tao Liu <[email protected]> 于2025年12月5日周五 06:40写道:
> >>
> >> Hi Guanyou,
> >>
> >> On Thu, Dec 4, 2025 at 11:33 PM Guanyou Chen <[email protected]>
> wrote:
> >> >
> >> > Hi Lianbo
> >> >
> >> > Kernel commit 55564814a838 ("arm64/mm: Move PTE_PRESENT_INVALID
> >> > to overlay PTE_NG"), which is contained in Linux 6.10 and
> >> > later kernels, changed the format of swap entries on arm64.
> >> > Without the patch, the "vtop" command cannot display swap information
> >> >
> >> > before:
> >> >     crash> vtop 2000000
> >> >     VIRTUAL     PHYSICAL
> >> >     2000000     (not mapped)
> >> >
> >> >     PAGE DIRECTORY: ffffff8106356000
> >> >        PGD: ffffff8106356000 => 800000186355003
> >> >        PMD: ffffff8106355080 => 8000001476f5003
> >> >        PTE: ffffff80c76f5000 => 101a62004
> >> >
> >> >        PTE       OFFSET: 1055330
> >> >     vtop: cannot determine swap location
> >> >
> >> > without the patch:
> >> >     crash> vtop 2000000
> >> >     VIRTUAL     PHYSICAL
> >> >     2000000     (not mapped)
> >> >
> >> >     PAGE DIRECTORY: ffffff8106356000
> >> >        PGD: ffffff8106356000 => 800000186355003
> >> >        PMD: ffffff8106355080 => 8000001476f5003
> >> >        PTE: ffffff80c76f5000 => 101a62004
> >> >
> >> >        PTE                     SWAP                  OFFSET
> >> >     101a62004  /first_stage_ramdisk/dev/block/zram0  1055330
> >> >
> >> >           VMA           START       END     FLAGS FILE
> >> >     ffffff81a06e8b00    2000000   22000000 100073
> >> >
> >> >     SWAP: /first_stage_ramdisk/dev/block/zram0  OFFSET: 1055330
> >> >
> >> > Link:
> https://lore.kernel.org/r/[email protected]
> >> > Signed-off-by: Guanyou.Chen <[email protected]>
> >> > ---
> >> >  arm64.c  | 11 ++++++++++-
> >> >  memory.c |  5 ++++-
> >> >  2 files changed, 14 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git a/arm64.c b/arm64.c
> >> > index 1723595..c125655 100644
> >> > --- a/arm64.c
> >> > +++ b/arm64.c
> >> > @@ -712,7 +712,16 @@ arm64_init(int when)
> >> >             }
> >> >         }
> >> >
> >> > -       if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
> >> > +       if (THIS_KERNEL_VERSION >= LINUX(6,10,0)) {
> >> > +           ms->__SWP_TYPE_BITS = 5;
> >> > +           ms->__SWP_TYPE_SHIFT = 6;
> >> > +           ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) - 1);
> >> > +           ms->__SWP_OFFSET_SHIFT = 12;
> >> > +           ms->__SWP_OFFSET_BITS = 50;
> >> > +           ms->__SWP_OFFSET_MASK = ((1UL << ms->__SWP_OFFSET_BITS) -
> 1);
> >> > +           ms->PTE_PROT_NONE = 0; /* unused */
> >> > +           ms->PTE_FILE = 0;  /* unused */
> >> > +       } else if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
>
> Sorry maybe I didn't make myself clear. What I mean is, the kernel
> link, aka
> https://lore.kernel.org/r/[email protected],
> updated the information as you have addressed above, and this part is
> OK to me.
>
> >> >             ms->__SWP_TYPE_BITS = 5;
> >> >             ms->__SWP_TYPE_SHIFT = 3;
> >> >             ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) - 1);
> >> > diff --git a/memory.c b/memory.c
> >> > index 400d31a..cbc8d2f 100644
> >> > --- a/memory.c
> >> > +++ b/memory.c
> >> > @@ -16415,6 +16415,8 @@ get_swapdev(ulong type, char *buf)
> >> >     ulong vfsmnt;
> >> >     char *devname;
> >> >     char buf1[BUFSIZE];
> >> > +   int swap_file_is_file =
> >> > +       STREQ(MEMBER_TYPE_NAME("swap_info_struct", "swap_file"),
> "file");
> >> >
> >> >     swap_info_init();
> >> >
> >> > @@ -16474,7 +16476,8 @@ get_swapdev(ulong type, char *buf)
> >> >             vfsmnt = ULONG(vt->swap_info_struct +
> >> >                 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) {
>
> But the link nor your commit log doesn't provide information for the
> above swap_file_is_file code change. Like why do you need to add the
> "|| swap_file_is_file" check here? Does it have any relations with the
> previous __SWP_TYPE_XXX value updating? What I'm trying to figure out
> is whether your __SWP_TYPE_XXX updating and swap_file_is_file
> checking, are independent of each other and should go into 2 seperated
> patches.
>
> >>
> >> Any reason for the extra swap_file_is_file check? From the kernel
> >> patch link you posted, only the __SWP_TYPE_XXX changes, which is
> >> presented in (THIS_KERNEL_VERSION >= LINUX(6,10,0), but no info
> >> related to swap_file_is_file check?
> >>
> >> Thanks,
> >> Tao Liu
> >>
> >>
> >> >             devname = vfsmount_devname(file_to_vfsmnt(swap_file),
> >> >                 buf1, BUFSIZE);
> >> >             get_pathname(file_to_dentry(swap_file),
> >> > --
> >> > 2.34.1
> >> >
> >> > Thanks.
> >> > Guanyou
> >>
>
>
From dd7572dabced347bfcd91249a25a262639fc60ba Mon Sep 17 00:00:00 2001
From: "Guanyou.Chen" <[email protected]>
Date: Fri, 5 Dec 2025 13:56:38 +0800
Subject: [PATCH 2/2] [2/2]arm64: Fix "vtop" command to display swap
 information on Linux 6.10 and later

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.

before:
    crash> vtop 2000000
    VIRTUAL     PHYSICAL
    2000000     (not mapped)

    PAGE DIRECTORY: ffffff8106356000
       PGD: ffffff8106356000 => 800000186355003
       PMD: ffffff8106355080 => 8000001476f5003
       PTE: ffffff80c76f5000 => 101a62004

       PTE       OFFSET: 1055330
    vtop: cannot determine swap location

after:
    crash> vtop 2000000
    VIRTUAL     PHYSICAL
    2000000     (not mapped)

    PAGE DIRECTORY: ffffff8106356000
       PGD: ffffff8106356000 => 800000186355003
       PMD: ffffff8106355080 => 8000001476f5003
       PTE: ffffff80c76f5000 => 101a62004

       PTE                     SWAP                  OFFSET
    101a62004  /first_stage_ramdisk/dev/block/zram0  1055330

          VMA           START       END     FLAGS FILE
    ffffff81a06e8b00    2000000   22000000 100073

    SWAP: /first_stage_ramdisk/dev/block/zram0  OFFSET: 1055330

Signed-off-by: Guanyou.Chen <[email protected]>
---
 memory.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/memory.c b/memory.c
index 400d31a..cbc8d2f 100644
--- a/memory.c
+++ b/memory.c
@@ -16415,6 +16415,8 @@ get_swapdev(ulong type, char *buf)
 	ulong vfsmnt;
 	char *devname;
 	char buf1[BUFSIZE];
+	int swap_file_is_file =
+		STREQ(MEMBER_TYPE_NAME("swap_info_struct", "swap_file"), "file");
 
 	swap_info_init();
 
@@ -16474,7 +16476,8 @@ get_swapdev(ulong type, char *buf)
 			vfsmnt = ULONG(vt->swap_info_struct + 
 				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) {
 			devname = vfsmount_devname(file_to_vfsmnt(swap_file),
 				buf1, BUFSIZE);
 			get_pathname(file_to_dentry(swap_file),
-- 
2.34.1

From 129500be327786b8fc6cad558922112b418fc92b Mon Sep 17 00:00:00 2001
From: "Guanyou.Chen" <[email protected]>
Date: Fri, 5 Dec 2025 13:55:30 +0800
Subject: [PATCH 1/2] [1/2]arm64: Fix "vtop" command to display swap
 information on Linux 6.10 and later

Kernel commit 55564814a838 ("arm64/mm: Move PTE_PRESENT_INVALID
to overlay PTE_NG"), which is contained in Linux 6.10 and
later kernels, changed the format of swap entries on arm64.
Without the patch, the "vtop" command cannot display swap information

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guanyou.Chen <[email protected]>
---
 arm64.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arm64.c b/arm64.c
index 1723595..c125655 100644
--- a/arm64.c
+++ b/arm64.c
@@ -712,7 +712,16 @@ arm64_init(int when)
 			}
 		}
 
-		if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
+		if (THIS_KERNEL_VERSION >= LINUX(6,10,0)) {
+			ms->__SWP_TYPE_BITS = 5;
+			ms->__SWP_TYPE_SHIFT = 6;
+			ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) - 1);
+			ms->__SWP_OFFSET_SHIFT = 12;
+			ms->__SWP_OFFSET_BITS = 50;
+			ms->__SWP_OFFSET_MASK = ((1UL << ms->__SWP_OFFSET_BITS) - 1);
+			ms->PTE_PROT_NONE = 0; /* unused */
+			ms->PTE_FILE = 0;  /* unused */
+		} else if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
 			ms->__SWP_TYPE_BITS = 5;
 			ms->__SWP_TYPE_SHIFT = 3;
 			ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) - 1);
-- 
2.34.1

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