Re: [Crash-utility] [PATCHv5 3/3] crash-utility/arm64: assign page_offset with kernel configure value

-----Original Message----- > On RHEL9, crash hits a bug when executing "crash /proc/kcore" : > seek error: kernel virtual address: ffff6a0f3fff0000 type: "pmd page" > > The kernel virtual address does not vary with va_actual bits, instead, > is determined by configuration value. But crash does not observe this > fact. > > Since this disagreement only happens if 52-bits kernel on 48 bits platform, > it can be handled only if "phys_offset_nominal < 0". > > Signed-off-by: Pingfan Liu <piliu(a)redhat.com&gt; > Cc: HAGIO KAZUHITO <k-hagio-ab(a)nec.com&gt; > Cc: Lianbo Jiang <lijiang(a)redhat.com&gt; > Cc: Bhupesh Sharma <bhupesh.sharma(a)linaro.org&gt; > To: crash-utility(a)redhat.com > --- > arm64.c | 10 +++++++++- > defs.h | 1 + > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arm64.c b/arm64.c > index f1bac84..7cc19e8 100644 > --- a/arm64.c > +++ b/arm64.c > @@ -221,7 +221,15 @@ arm64_init(int when) > arm64_calc_VA_BITS(); > arm64_calc_KERNELPACMASK(); > ms = machdep->machspec; > - if (ms->VA_BITS_ACTUAL) { > + /* For 52-bits kernel running on 48 bits platform */ > + if (ms->phys_offset_nominal < 0) { Maybe I miss something, is the ms->phys_offset_nominal set at this point?

if (ms->phys_offset_nominal < 0) { ... /* use machdep parameters */ arm64_calc_phys_offset(); <<-- set here? arm64_calc_physvirt_offset(); Thanks, Kazu > + ms->page_offset = ARM64_FLIP_PAGE_OFFSET; > + /* useless on arm64 */ > + machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET; > + machdep->kvbase = ARM64_FLIP_PAGE_OFFSET; > + ms->userspace_top = ARM64_USERSPACE_TOP_ACTUAL; > + /* For 52-bits on 52-bits platform, or 48-bits on 48 */ > + } else if (ms->VA_BITS_ACTUAL) { > ms->page_offset = ARM64_FLIP_PAGE_OFFSET_ACTUAL; > machdep->identity_map_base = ARM64_FLIP_PAGE_OFFSET_ACTUAL; > machdep->kvbase = ARM64_FLIP_PAGE_OFFSET_ACTUAL; > diff --git a/defs.h b/defs.h > index 1007c69..f804212 100644 > --- a/defs.h > +++ b/defs.h > @@ -3224,6 +3224,7 @@ typedef signed int s32; > #define ARM64_PAGE_OFFSET ((0xffffffffffffffffUL) \ > << (machdep->machspec->VA_BITS - 1)) > /* kernels > v5.4 the kernel VA space is flipped */ > +#define ARM64_FLIP_PAGE_OFFSET (-(1UL) << machdep->machspec->CONFIG_ARM64_VA_BITS) > #define ARM64_FLIP_PAGE_OFFSET_ACTUAL ((0xffffffffffffffffUL) \ > - ((1UL) << machdep->machspec->VA_BITS_ACTUAL) + 1) > > -- > 2.29.2