pm24.git/arch/powerpc/kernel/stacktrace.c, branch v5.6

powerpc/ftrace: Enable HAVE_FUNCTION_GRAPH_RET_ADDR_PTR

2019-09-18T02:24:55Z

This associates entries in the ftrace_ret_stack with corresponding stack frames, enabling more robust stack unwinding. Also update the only user of ftrace_graph_ret_addr() to pass the stack pointer. Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0224f2d0971b069c678e2ff678cfc2cd1e114cfe.1567707399.git.naveen.n.rao@linux.vnet.ibm.com

powerpc: Remove export of save_stack_trace_tsk_reliable()

2019-03-02T03:43:05Z

As tglx points out, there are no in-tree module users of save_stack_trace_tsk_reliable() and its x86 counterpart is not exported, so remove the powerpc symbol export. Suggested-by: Thomas Gleixner Signed-off-by: Joe Lawrence Signed-off-by: Michael Ellerman

powerpc: prep stack walkers for THREAD_INFO_IN_TASK

2019-02-23T11:31:40Z

[text copied from commit 9bbd4c56b0b6 ("arm64: prep stack walkers for THREAD_INFO_IN_TASK")] When CONFIG_THREAD_INFO_IN_TASK is selected, task stacks may be freed before a task is destroyed. To account for this, the stacks are refcounted, and when manipulating the stack of another task, it is necessary to get/put the stack to ensure it isn't freed and/or re-used while we do so. This patch reworks the powerpc stack walking code to account for this. When CONFIG_THREAD_INFO_IN_TASK is not selected these perform no refcounting, and this should only be a structural change that does not affect behaviour. Acked-by: Mark Rutland Signed-off-by: Christophe Leroy Reviewed-by: Nicholas Piggin [mpe: Move try_get_task_stack() below tsk == NULL check in show_stack()] Signed-off-by: Michael Ellerman

powerpc/livepatch: return -ERRNO values in save_stack_trace_tsk_reliable()

2019-01-31T05:43:38Z

To match its x86 counterpart, save_stack_trace_tsk_reliable() should return -EINVAL in cases that it is currently returning 1. No caller is currently differentiating non-zero error codes, but let's keep the arch-specific implementations consistent. Signed-off-by: Joe Lawrence Signed-off-by: Michael Ellerman

powerpc/livepatch: small cleanups in save_stack_trace_tsk_reliable()

2019-01-31T05:43:38Z

Mostly cosmetic changes: - Group common stack pointer code at the top - Simplify the first frame logic - Code stackframe iteration into for...loop construct - Check for trace->nr_entries overflow before adding any into the array Suggested-by: Nicolai Stange Signed-off-by: Joe Lawrence Signed-off-by: Michael Ellerman

powerpc/livepatch: relax reliable stack tracer checks for first-frame

2019-01-31T05:43:38Z

The bottom-most stack frame (the first to be unwound) may be largely uninitialized, for the "Power Architecture 64-Bit ELF V2 ABI" only requires its backchain pointer to be set. The reliable stack tracer should be careful when verifying this frame: skip checks on STACK_FRAME_LR_SAVE and STACK_FRAME_MARKER offsets that may contain uninitialized residual data. Fixes: df78d3f61480 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model") Signed-off-by: Joe Lawrence Signed-off-by: Michael Ellerman

powerpc/64s: Fix build failures with CONFIG_NMI_IPI=n

2018-06-19T13:03:50Z

I broke the build when CONFIG_NMI_IPI=n with my recent commit to add arch_trigger_cpumask_backtrace(), eg: stacktrace.c:(.text+0x1b0): undefined reference to `.smp_send_safe_nmi_ipi' We should rework the CONFIG symbols here in future to avoid these double barrelled ifdefs but for now they fix the build. Fixes: 5cc05910f26e ("powerpc/64s: Wire up arch_trigger_cpumask_backtrace()") Reported-by: Christophe LEROY Signed-off-by: Michael Ellerman

powerpc/stacktrace: Update copyright

2018-06-03T10:43:43Z

This now has new code in it written by Nick and I, and switch to a SPDX tag. Signed-off-by: Michael Ellerman Reviewed-by: Nicholas Piggin

powerpc/64s: Wire up arch_trigger_cpumask_backtrace()

2018-06-03T10:43:43Z

This allows eg. the RCU stall detector, or the soft/hardlockup detectors to trigger a backtrace on all CPUs. We implement this by sending a "safe" NMI, which will actually only send an IPI. Unfortunately the generic code prints "NMI", so that's a little confusing but we can probably live with it. If one of the CPUs doesn't respond to the IPI, we then print some info from it's paca and do a backtrace based on its saved_r1. Example output: INFO: rcu_sched detected stalls on CPUs/tasks: 2-...0: (0 ticks this GP) idle=1be/1/4611686018427387904 softirq=1055/1055 fqs=25735 (detected by 4, t=58847 jiffies, g=58, c=57, q=1258) Sending NMI from CPU 4 to CPUs 2: CPU 2 didn't respond to backtrace IPI, inspecting paca. irq_soft_mask: 0x01 in_mce: 0 in_nmi: 0 current: 3623 (bash) Back trace of paca->saved_r1 (0xc0000000e1c83ba0) (possibly stale): Call Trace: [c0000000e1c83ba0] [0000000000000014] 0x14 (unreliable) [c0000000e1c83bc0] [c000000000765798] lkdtm_do_action+0x48/0x80 [c0000000e1c83bf0] [c000000000765a40] direct_entry+0x110/0x1b0 [c0000000e1c83c90] [c00000000058e650] full_proxy_write+0x90/0xe0 [c0000000e1c83ce0] [c0000000003aae3c] __vfs_write+0x6c/0x1f0 [c0000000e1c83d80] [c0000000003ab214] vfs_write+0xd4/0x240 [c0000000e1c83dd0] [c0000000003ab5cc] ksys_write+0x6c/0x110 [c0000000e1c83e30] [c00000000000b860] system_call+0x58/0x6c Signed-off-by: Michael Ellerman Reviewed-by: Nicholas Piggin

powerpc/livepatch: Fix build error with kprobes disabled.

2018-05-29T01:10:39Z

arch/powerpc/kernel/stacktrace.c: In function ‘save_stack_trace_tsk_reliable’: arch/powerpc/kernel/stacktrace.c:176:28: error: ‘kretprobe_trampoline’ undeclared if (ip == (unsigned long)kretprobe_trampoline) ^~~~~~~~~~~~~~~~~~~~ Fixes: df78d3f61480 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model") Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman