[Crash-utility] Re: [PATCH] arm64: Fix "vtop" command to display swap information on Linux 6.10 and later

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 <ltao(a)redhat.com&gt; 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 <chenguanyou9338(a)gmail.com&gt; 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/20240503144604.151095-4-ryan.roberts@arm.com > > Signed-off-by: Guanyou.Chen <chenguanyou(a)xiaomi.com&gt; > > --- > > 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)) {

> > 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) {

> > 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 >