In RHEL 9.4 ppc64le, the stack size was adjusted from 16k to 32k. This can cause ppc64_back_trace() to bail prematurely since SIZE(irq_ctx), used in ppc64_in_irqstack(), is set to 16k. This patch ensures that irq_ctx is updated to 32k when task_init() executes, which occurs just before other variables are initalized using the incorrectly sized irq_ctx. Tested on: x86_64, s390x, aarch64, ppc64le Without the commit: crash> bt -c 3 PID: 17524 TASK: c0000000b2c0e400 CPU: 3 COMMAND: "xyz" cannot find the stack info. With the commit: crash> bt -c 3 PID: 17524 TASK: c0000000b2c0e400 CPU: 3 COMMAND: "xyz" #0 [c000001dff7d7c10] smp_call_function_single_async at c00000000028dd38 #1 [c000001dff7d7d30] _raw_spin_lock_irqsave at c000000001023f1c #2 [c000001dff7d7d60] ibmvscsi_handle_crq at c0080000044635ec [ibmvscsi] #3 [c000001dff7d7de0] ibmvscsi_task at c008000004463804 [ibmvscsi] #4 [c000001dff7d7e30] tasklet_action_common.constprop.0 at c0000000001624cc #5 [c000001dff7d7e90] __do_softirq at c0000000010244cc #6 [c000001dff7d7f90] do_softirq_own_stack at c000000000016480 #7 [c000000140d67700] __irq_exit_rcu at c0000000001613b8 #8 [c000000140d67730] irq_exit at c000000000162170 #9 [c000000140d67750] do_IRQ at c000000000015fa4 #10 [c000000140d67780] hardware_interrupt_common_virt at c000000000009080 Hardware Interrupt [500] exception frame: R0: c000000001023de0 R1: c000000140d67a90 R2: c000000002c02500 R3: c00800000b30269c R4: 0000000000000001 R5: 0000000000000001 R6: ffffffffffffffff R7: 0000000000000000 R8: 0000000000000000 R9: fffffffffffe0000 R10: 0000000000000002 R11: 0000000048422824 R12: c000000001023d70 R13: c000001dffffd480 R14: 00007ffd6ef6d238 R15: 0000000000000028 R16: c000001dfc1e2280 R17: c000001dfc1e2280 R18: 00000000ab97fa48 R19: 0000000000000000 R20: 0000000000000001 R21: 0000001df9ff0000 R22: 0000000000000028 R23: c0000000021f2280 R24: 0000000000000000 R25: c0000000021f2280 R26: c0000000021f2380 R27: 0000000000000000 R28: c00800000b30269c R29: 0000000000000000 R30: c000000002c47190 R31: 000000000020000b NIP: c0000000000aea14 MSR: 800000000280b033 OR3: c0000000000ae944 CTR: c000000001023d70 LR: c000000001023de0 XER: 0000000020040001 CCR: 0000000088422824 MQ: 0000000000000000 DAR: 0000000000000001 DSISR: c0080000073b1e94 Syscall Result: 0000000000000000 [NIP : queued_spin_lock_slowpath+1204] [LR : _raw_spin_lock+112] #11 [c000000140d67a90] queued_spin_lock_slowpath at c0000000000aea14 #12 [c000000140d67bb0] _raw_spin_lock at c000000001023de0 (unreliable) #13 [c000000140d67bd0] dm_blk_close at c00800000b2c6850 [dm_mod] #14 [c000000140d67c00] blkdev_put_whole at c0000000007d2738 #15 [c000000140d67c30] bdev_release at c0000000007d3a38 #16 [c000000140d67c90] blkdev_release at c0000000007d4224 #17 [c000000140d67cb0] __fput at c0000000005d2e98 #18 [c000000140d67d00] task_work_run at c00000000018fb14 #19 [c000000140d67d50] do_notify_resume at c000000000020bd4 #20 [c000000140d67d80] interrupt_exit_user_prepare_main at c00000000002ed98 #21 [c000000140d67de0] syscall_exit_prepare at c00000000002f240 #22 [c000000140d67e10] system_call_vectored_common at c00000000000bff4 Signed-off-by: Lucas Oakley <soakley(a)redhat.com&gt; --- task.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/task.c b/task.c index ec04b55..46d46bf 100644 --- a/task.c +++ b/task.c @@ -497,6 +497,17 @@ task_init(void) } else if (VALID_SIZE(thread_union) && ((len = SIZE(thread_union)) != STACKSIZE())) { machdep->stacksize = len; + /* + * RHEL 9.4.z adjusted the stack size from 16k to 32k for + * ppc64le only. We need to ensure that SIZE(irq_ctx) is + * correctly set so the unwinder doesn't prematurely bail + * when switching stacks. The stack size is updated in + * task_init(), so ensure irq_ctx is updated here. I'm + * adjusting it here since allocations referencing irq_ctx + * can occur promptly after this point. + */ + if (SIZE(irq_ctx) != -1) + ASSIGN_SIZE(irq_ctx) = len; } else if (!VALID_SIZE(thread_union) && !VALID_SIZE(task_union)) { len = 0; if (kernel_symbol_exists("__start_init_stack") && -- 2.52.0 -- Crash-utility mailing list -- devel(a)lists.crash-utility.osci.io To unsubscribe send an email to devel-leave(a)lists.crash-utility.osci.io https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ Contribution Guidelines: https://github.com/crash-utility/crash/wiki