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 vabits_actual related kernel commit is introduced after arm64 mm layout flip commit, so changes are safe under the condition if (ms->VA_BITS_ACTUAL), and keep else branch untouched. Signed-off-by: Pingfan Liu <[email protected]> Cc: HAGIO KAZUHITO <[email protected]> Cc: Lianbo Jiang <[email protected]> Cc: Bhupesh Sharma <[email protected]> To: [email protected] --- arm64.c | 7 ++++--- defs.h | 1 + 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/arm64.c b/arm64.c index 9fe1a4a..149db36 100644 --- a/arm64.c +++ b/arm64.c @@ -220,9 +220,10 @@ arm64_init(int when) /* vabits_actual introduced after mm flip, so it should be flipped layout */ 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; + 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; } else { ms->page_offset = ARM64_PAGE_OFFSET; diff --git a/defs.h b/defs.h index af0dc8f..60dcd39 100644 --- a/defs.h +++ b/defs.h @@ -3233,6 +3233,7 @@ 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 -- Crash-utility mailing list [email protected] https://listman.redhat.com/mailman/listinfo/crash-utility
