There is a regression been found for xen hyper due to the commit: f615f8fab7bf ("Fix "irq -a" exceeding the memory range issue"). The reason is for xen hyper, kt->cpu is not initialized due to kernel_init() won't be called. So 0 would be assigned to cpulen and fails the GETBUF(). Before: crash> bt -c 2 bt: zero-size memory allocation! (called from 51f168) After: crash> bt -c 2 PCPU: 0 VCPU: ffff8300001b8080 #0 [ffff8300001bfe00] machine_crash_kexec at ffff83000010de72 #1 [ffff8300001bfe10] do_kexec_op at ffff83000010e3cb #2 [ffff8300001bfe50] do_console_io at ffff83000011aff4 #3 [ffff8300001bfe90] mod_l1_entry at ffff830000129045 #4 [ffff8300001bfea0] toggle_guest_mode at ffff8300001641bf #5 [ffff8300001bfeb0] do_iret at ffff830000164888 #6 [ffff8300001bff20] syscall_enter at ffff8300001633d2 Since xen hyper will initialize its own cpumask_t, this patch will reuse it for XEN_HYPER_MODE. Signed-off-by: Tao Liu <ltao(a)redhat.com&gt; --- Link to v1: https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01080.html v1 -> v2: 1) Remove "xen_hyper_defs.h" include for tools.c. 2) Modified the same code hunk in generic_get_irq_affinity(). Note this patch will cause a small merge conflict with the NO.2 patch[1] of the v7 gdb stack unwinding support. Should be easy to fix since it has no functional modification on [1]. [1]: https://www.mail-archive.com/devel@lists.crash-utility.osci.io/msg01081.html --- defs.h | 3 +++ kernel.c | 10 ++++++---- tools.c | 3 +++ xen_hyper.c | 9 +++++++++ 4 files changed, 21 insertions(+), 4 deletions(-) diff --git a/defs.h b/defs.h index dfbd241..94f86e6 100644 --- a/defs.h +++ b/defs.h @@ -8031,6 +8031,9 @@ extern int have_full_symbols(void); #if defined(X86) || defined(X86_64) || defined(IA64) #define XEN_HYPERVISOR_ARCH +long xen_get_cpumask_size(void); +#else +#define xen_get_cpumask_size() -1 #endif /* diff --git a/kernel.c b/kernel.c index adb19ad..56deb3a 100644 --- a/kernel.c +++ b/kernel.c @@ -7382,10 +7382,12 @@ generic_get_irq_affinity(int irq) if (!action) return; - len = DIV_ROUND_UP(kt->cpus, BITS_PER_LONG) * sizeof(ulong); - len_cpumask = STRUCT_SIZE("cpumask_t"); - if (len_cpumask > 0) - len = len_cpumask > len ? len : len_cpumask; + if (!XEN_HYPER_MODE() || (len = xen_get_cpumask_size()) < 0) { + len = DIV_ROUND_UP(kt->cpus, BITS_PER_LONG) * sizeof(ulong); + len_cpumask = STRUCT_SIZE("cpumask_t"); + if (len_cpumask > 0) + len = len_cpumask > len ? len : len_cpumask; + } affinity = (ulong *)GETBUF(len); if (VALID_MEMBER(irq_common_data_affinity)) diff --git a/tools.c b/tools.c index 2b78b95..c4fe9c8 100644 --- a/tools.c +++ b/tools.c @@ -6720,6 +6720,9 @@ get_cpumask_buf(void) { int cpulen, len_cpumask; + if (XEN_HYPER_MODE() && (cpulen = xen_get_cpumask_size()) >= 0) + return (ulong *)GETBUF(cpulen); + cpulen = DIV_ROUND_UP(kt->cpus, BITS_PER_LONG) * sizeof(ulong); len_cpumask = STRUCT_SIZE("cpumask_t"); if (len_cpumask > 0) diff --git a/xen_hyper.c b/xen_hyper.c index 32e56fa..db2dd6f 100644 --- a/xen_hyper.c +++ b/xen_hyper.c @@ -2201,4 +2201,13 @@ xen_hyper_print_bt_header(FILE *out, ulong vcpu, int newline) error(FATAL, "invalid vcpu\n"); fprintf(out, "PCPU: %2d VCPU: %lx\n", vcc->processor, vcpu); } + +long +xen_get_cpumask_size(void) +{ + if (XEN_HYPER_VALID_SIZE(cpumask_t)) + return XEN_HYPER_SIZE(cpumask_t); + else + return -1; +} #endif -- 2.40.1