Hi Alexey,
On Sat, Mar 16, 2024 at 6:15 AM Alexey Makhalov
<alexey.makhalov@xxxxxxxxxxxx> wrote:
>
> Hi Tao,
>
> Thanks for the details. Agree, my approach is targeted primarily for offline debugging.
> Create/exit monitoring sounds like an overkill. And from the other side, maintaining a static list of threads (CPUs or Tasks) does not work for live debugging.
> "ps" followed by "set" where GDB will receive just one inferior/thread at a time is probably the right universal approach.
> Let me experiment with a combination of my and your patches and come back to you.
>
Thanks, that would be great, looking forward for the combination!
Thanks,
Tao Liu
> Thanks,
> --Alexey
>
>
> On Thu, Mar 14, 2024 at 9:22 PM Tao Liu <ltao@xxxxxxxxxx> wrote:
>>
>> Hi Alexey,
>>
>> On Thu, Mar 14, 2024 at 6:29 PM Alexey Makhalov
>> <alexey.makhalov@xxxxxxxxxxxx> wrote:
>> >
>> > Support for GDB debugging of all tasks active and inactive.
>> > Before this commit only active tasks were listed by "info threads"
>> > with "CPU #" as a Target Id.
>> >
>> > "info threads" will now show all tasks, similar to "ps", example:
>> > crash> info threads
>> > Id Target Id Frame
>> > * 1 0 swapper/0 0xffffffffadba19d4 in default_idle () at arch/x86/kernel/process.c:731
>> > 2 0 swapper/1 0xffffffffadba19d4 in default_idle () at arch/x86/kernel/process.c:731
>> > 3 0 swapper/2 0xffffffffadba19d4 in default_idle () at arch/x86/kernel/process.c:731
>> > 4 0 swapper/3 0xffffffffadba19d4 in default_idle () at arch/x86/kernel/process.c:731
>> > 5 0 swapper/4 0xffffffffadb97292 in context_switch (rf=0xffffbaf0000f3e88, next=0xffff9ecb04908000, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > ...
>> > 730 970325 taskset 0xffffffffadb97292 in context_switch (rf=0xffffbaf006a0fd18, next=0xffff9ecb0aec0000, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > 731 975217 sleep 0xffffffffadb97292 in context_switch (rf=0xffffbaf005743c20, next=0xffff9ecac0692880, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > 732 975228 sleep 0xffffffffadb97292 in context_switch (rf=0xffffbaf00696fb58, next=0xffff9ecac0690000, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > ...
>> > 876 976084 docker 0xffffffffadb97292 in context_switch (rf=0xffffbaf0153dbd10, next=0xffff9ecac0645100, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > 877 976085 systemd-userwor 0xffffffffadb97292 in context_switch (rf=0xffffbaf0153cbc58, next=0xffff9ecac0645100, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > 878 976086 systemd-userwor 0xffffffffadb97292 in context_switch (rf=0xffffbaf0153e3c58, next=0xffffffffaec15a40 <init_task>, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > 879 976087 systemd-userwor 0xffffffffadb97292 in context_switch (rf=0xffffbaf0153ebc58, next=0xffffffffaec15a40 <init_task>, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > Where "Target ID" contains "PID COMM" of the task
>> >
>>
>> I see here, we chose a different tech path of viewing arbitrary tasks.
>> You improved the "info threads" as an alternative to crash "ps" cmd,
>> and use "thread X" to switch to task X and view its stacktrace.
>> However mine is using crash "ps" cmd first, getting specific tasks pid
>> or task struct, then using crash cmd "set <pid>" or "set
>> <task_struct>" to switch to task X and view its stacktrace.
>>
>> I notice there is one problem of using the "info threads as ps" tech
>> path, it is difficult to handle the live debug, see the comment below:
>>
>> > Example of "731 975217 sleep" debugging, real case, trying to
>> > figure out why sleep was stuck in uninterruptable sleep.
>> > Backtrace using crash:
>> > crash> ps | grep 975217
>> > 975217 969797 3 ffff9ecb3956a880 UN 0.0 0 0 sleep
>> > crash> bt 975217
>> > PID: 975217 TASK: ffff9ecb3956a880 CPU: 3 COMMAND: "sleep"
>> > #0 [ffffbaf005743ba0] __schedule at ffffffffadb97292
>> > #1 [ffffbaf005743c60] schedule at ffffffffadb982b8
>> > #2 [ffffbaf005743c80] rwbase_write_lock at ffffffffadb9aed7
>> > #3 [ffffbaf005743cc0] down_write at ffffffffadb9b133
>> > #4 [ffffbaf005743cd0] unlink_file_vma at ffffffffad2b0e2e
>> > #5 [ffffbaf005743cf8] free_pgtables at ffffffffad2a47b0
>> > #6 [ffffbaf005743d88] exit_mmap at ffffffffad2b3b8d
>> > #7 [ffffbaf005743e80] mmput at ffffffffad08c81f
>> > #8 [ffffbaf005743e98] do_exit at ffffffffad09636c
>> > #9 [ffffbaf005743ef8] do_group_exit at ffffffffad096c78
>> > RIP: 00007f111c70ddf9 RSP: 00007fff451817e8 RFLAGS: 00000246
>> > RAX: ffffffffffffffda RBX: 00007f111c8089e0 RCX: 00007f111c70ddf9
>> > RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
>> > RBP: 0000000000000000 R8: ffffffffffffff80 R9: 0000000000000000
>> > R10: 00007fff451817b0 R11: 0000000000000246 R12: 00007f111c8089e0
>> > R13: 00007f111c80e2e0 R14: 0000000000000002 R15: 00007f111c80e2c8
>> > ORIG_RAX: 00000000000000e7 CS: 0033 SS: 002b
>> >
>> > Backtrace using gdb (pay attention, task must be selected by thread Id):
>> > crash> thread 731
>> > [Switching to thread 731 ( 975217 sleep)]
>> > 5372 switch_to(prev, next, prev);
>> > crash> gdb bt
>> > #0 0xffffffffadb97292 in context_switch (rf=0xffffbaf005743c20, next=0xffff9ecac0692880, prev=<optimized out>, rq=<optimized out>) at kernel/sched/core.c:5372
>> > #1 __schedule (sched_mode=sched_mode@entry=0) at kernel/sched/core.c:6696
>> > #2 0xffffffffadb982b8 in schedule () at kernel/sched/core.c:6772
>> > #3 0xffffffffadb9aed7 in rwbase_write_lock (rwb=rwb@entry=0xffff9ecaf1831430, state=state@entry=2) at kernel/locking/rwbase_rt.c:259
>> > #4 0xffffffffadb9b133 in __down_write (sem=sem@entry=0xffff9ecaf1831430) at kernel/locking/rwsem.c:1474
>> > #5 down_write (sem=sem@entry=0xffff9ecaf1831430) at kernel/locking/rwsem.c:1574
>> > #6 0xffffffffad2b0e2e in i_mmap_lock_write (mapping=<optimized out>) at ./include/linux/fs.h:466
>> > #7 unlink_file_vma (vma=vma@entry=0xffff9ecadd566090) at mm/mmap.c:127
>> > #8 0xffffffffad2a47b0 in free_pgtables (tlb=tlb@entry=0xffffbaf005743dd0, mt=mt@entry=0xffff9ecb28e3b180, vma=0xffff9ecadd566090, vma@entry=0xffff9ecadd566000, floor=floor@entry=0, ceiling=ceiling@entry=0) at mm/memory.c:431
>> > #9 0xffffffffad2b3b8d in exit_mmap (mm=mm@entry=0xffff9ecb28e3b180) at mm/mmap.c:3237
>> > #10 0xffffffffad08c81f in __mmput (mm=0xffff9ecb28e3b180) at kernel/fork.c:1204
>> > #11 mmput (mm=mm@entry=0xffff9ecb28e3b180) at kernel/fork.c:1226
>> > #12 0xffffffffad09636c in exit_mm () at kernel/exit.c:563
>> > #13 do_exit (code=code@entry=0) at kernel/exit.c:856
>> > #14 0xffffffffad096c78 in do_group_exit (exit_code=0) at kernel/exit.c:1019
>> > #15 0xffffffffad096cf8 in __do_sys_exit_group (error_code=<optimized out>) at kernel/exit.c:1030
>> > #16 __se_sys_exit_group (error_code=<optimized out>) at kernel/exit.c:1028
>> > #17 __x64_sys_exit_group (regs=<optimized out>) at kernel/exit.c:1028
>> > #18 0xffffffffadb8a327 in do_syscall_x64 (nr=<optimized out>, regs=0xffffbaf005743f58) at arch/x86/entry/common.c:51
>> > #19 do_syscall_64 (regs=0xffffbaf005743f58, nr=<optimized out>) at arch/x86/entry/common.c:81
>> > #20 0xffffffffadc000dc in entry_SYSCALL_64 () at arch/x86/entry/entry_64.S:120
>> > #21 0x00007f111c80e2c8 in ?? ()
>> > #22 0x0000000000000002 in ?? ()
>> > #23 0x00007f111c80e2e0 in ?? ()
>> > #24 0x00007f111c8089e0 in ?? ()
>> > #25 0x0000000000000000 in ?? ()
>> > crash> f 3
>> > 259 rwbase_schedule();
>> > crash> p *rwb
>> > $1 = {
>> > readers = {
>> > counter = 1
>> > },
>> > rtmutex = {
>> > wait_lock = {
>> > raw_lock = {
>> > {
>> > val = {
>> > counter = 0
>> > },
>> > {
>> > locked = 0 '\000',
>> > pending = 0 '\000'
>> > },
>> > {
>> > locked_pending = 0,
>> > tail = 0
>> > }
>> > }
>> > }
>> > },
>> > waiters = {
>> > rb_root = {
>> > rb_node = 0xffffbaf006977be0
>> > },
>> > rb_leftmost = 0xffffbaf00696fbe0
>> > },
>> > owner = 0xffff9ecb3956a881
>> > }
>> > }
>> >
>> > Additional changes:
>> > 1. Allow gdb "frame" command.
>> > 2. Blacklist useless gdb "gcore" command. Use gcore plugin instead.
>> > 3. Move crash_target_init() to later time as crash target requires a list of
>> > tasks to be initialized.
>> >
>> > Known issues and TBD items:
>> > 1. "info threads" may bail out first time throwing errors trying to access
>> > userspace address during unwind process. Following "info threads"
>> > invokations run without issues.
>> > 2. To unwind a stack of inactive task, only modern Linux versions, which use
>> > inactive_task_frame, are supported and only x86_64 architecture.
>> > 3. gdb bt unwinder does not stop properly and may show invalid frames (21-25
>> > on example above). Not a regression, existed before.
>> > 4. gdb bt unwinder does not work on active tasks in userspace. Not a regression,
>> > existed before.
>> > 5. Only x86_64 architecture supported. machdep->get_task_reg() must be
>> > implemented for others. Not a regression, existed before.
>> > 6. Active tasks registers fetching imlemented only for VMware dumps, see
>> > x86_64_get_task_reg() for more details. Not a regression, existed before.
>> >
>> > Signed-off-by: Alexey Makhalov <alexey.makhalov@xxxxxxxxxxxx>
>> > ---
>> > crash_target.c | 39 ++++++++++++++++++++---------
>> > defs.h | 10 ++++++--
>> > gdb-10.2.patch | 7 ++----
>> > gdb_interface.c | 63 ++++++++++++++++++++++++++++++----------------
>> > help.c | 1 +
>> > main.c | 1 +
>> > task.c | 1 +
>> > x86_64.c | 66 +++++++++++++++++++++++++++++++++++++++++++------
>> > 8 files changed, 140 insertions(+), 48 deletions(-)
>> >
>> > diff --git a/crash_target.c b/crash_target.c
>> > index 4554806..2fdf203 100644
>> > --- a/crash_target.c
>> > +++ b/crash_target.c
>> > @@ -2,6 +2,8 @@
>> > * crash_target.c
>> > *
>> > * Copyright (c) 2021 VMware, Inc.
>> > + * Copyright (c) 2024 Broadcom. All Rights Reserved. The term "Broadcom"
>> > + * refers to Broadcom Inc. and/or its subsidiaries.
>> > *
>> > * This program is free software; you can redistribute it and/or modify
>> > * it under the terms of the GNU General Public License as published by
>> > @@ -13,7 +15,7 @@
>> > * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> > * GNU General Public License for more details.
>> > *
>> > - * Author: Alexey Makhalov <amakhalov@xxxxxxxxxx>
>> > + * Author: Alexey Makhalov <alexey.makhalov@xxxxxxxxxxxx>
>> > */
>> >
>> > #include <defs.h>
>> > @@ -23,11 +25,11 @@
>> > #include "regcache.h"
>> > #include "gdbarch.h"
>> >
>> > -void crash_target_init (void);
>> > -
>> > +extern "C" void crash_target_init (void);
>> > extern "C" int gdb_readmem_callback(unsigned long, void *, int, int);
>> > -extern "C" int crash_get_nr_cpus(void);
>> > -extern "C" int crash_get_cpu_reg (int cpu, int regno, const char *regname,
>> > +extern "C" int crash_get_nr_tasks(void);
>> > +extern "C" void crash_get_task_info(int task_nr, unsigned long *pid, char **comm);
>> > +extern "C" int crash_get_task_reg (int task_nr, int regno, const char *regname,
>> > int regsize, void *val);
>> >
>> >
>> > @@ -60,7 +62,13 @@ public:
>> > bool has_registers () override { return true; }
>> > bool thread_alive (ptid_t ptid) override { return true; }
>> > std::string pid_to_str (ptid_t ptid) override
>> > - { return string_printf ("CPU %ld", ptid.tid ()); }
>> > + {
>> > + unsigned long pid;
>> > + char *comm;
>> > +
>> > + crash_get_task_info(ptid.tid(), &pid, &comm);
>> > + return string_printf ("%7ld %s", pid, comm);
>> > + }
>> >
>> > };
>> >
>> > @@ -68,18 +76,25 @@ public:
>> > void
>> > crash_target::fetch_registers (struct regcache *regcache, int regno)
>> > {
>> > + int r;
>> > gdb_byte regval[16];
>> > - int cpu = inferior_ptid.tid();
>> > + int task_nr = inferior_ptid.tid();
>> > struct gdbarch *arch = regcache->arch ();
>> >
>> > - for (int r = 0; r < gdbarch_num_regs (arch); r++)
>> > + if (regno >= 0) {
>> > + r = regno;
>> > + goto onetime;
>> > + }
>> > +
>> > + for (r = 0; regno == -1 && r < gdbarch_num_regs (arch); r++)
>> > {
>> > +onetime:
>> > const char *regname = gdbarch_register_name(arch, r);
>> > int regsize = register_size (arch, r);
>> > if (regsize > sizeof (regval))
>> > error (_("fatal error: buffer size is not enough to fit register value"));
>> >
>> > - if (crash_get_cpu_reg (cpu, r, regname, regsize, (void *)®val))
>> > + if (crash_get_task_reg (task_nr, r, regname, regsize, (void *)®val))
>> > regcache->raw_supply (r, regval);
>> > else
>> > regcache->raw_supply (r, NULL);
>> > @@ -107,10 +122,10 @@ crash_target::xfer_partial (enum target_object object, const char *annex,
>> >
>> > #define CRASH_INFERIOR_PID 1
>> >
>> > -void
>> > +extern "C" void
>> > crash_target_init (void)
>> > {
>> > - int nr_cpus = crash_get_nr_cpus();
>> > + int nr_tasks = crash_get_nr_tasks();
>> > crash_target *target = new crash_target ();
>> >
>> > /* Own the target until it is successfully pushed. */
>> > @@ -119,7 +134,7 @@ crash_target_init (void)
>> > push_target (std::move (target_holder));
>> >
>> > inferior_appeared (current_inferior (), CRASH_INFERIOR_PID);
>> > - for (int i = 0; i < nr_cpus; i++)
>> > + for (int i = 0; i < nr_tasks; i++)
>> > {
>> > thread_info *thread = add_thread_silent (target,
>> > ptid_t(CRASH_INFERIOR_PID, 0, i));
>> > diff --git a/defs.h b/defs.h
>> > index 98650e8..2b3f247 100644
>> > --- a/defs.h
>> > +++ b/defs.h
>> > @@ -1080,7 +1080,7 @@ struct machdep_table {
>> > void (*get_irq_affinity)(int);
>> > void (*show_interrupts)(int, ulong *);
>> > int (*is_page_ptr)(ulong, physaddr_t *);
>> > - int (*get_cpu_reg)(int, int, const char *, int, void *);
>> > + int (*get_task_reg)(struct task_context *, int, const char *, int, void *);
>> > int (*is_cpu_prstatus_valid)(int cpu);
>> > };
>> >
>> > @@ -2263,6 +2263,7 @@ struct size_table { /* stash of commonly-used sizes */
>> > long pt_regs;
>> > long task_struct;
>> > long thread_info;
>> > + long inactive_task_frame;
>> > long softirq_state;
>> > long desc_struct;
>> > long umode_t;
>> > @@ -8001,9 +8002,14 @@ extern int have_full_symbols(void);
>> > #define XEN_HYPERVISOR_ARCH
>> > #endif
>> >
>> > +/*
>> > + * crash_target.c
>> > + */
>> > +extern void crash_target_init (void);
>> > +
>> > /*
>> > * Register numbers must be in sync with gdb/features/i386/64bit-core.c
>> > - * to make crash_target->fetch_registers() ---> machdep->get_cpu_reg()
>> > + * to make crash_target->fetch_registers() ---> machdep->get_task_reg()
>> > * working properly.
>> > */
>> > enum x86_64_regnum {
>> > diff --git a/gdb-10.2.patch b/gdb-10.2.patch
>> > index a7018a2..ecf673d 100644
>> > --- a/gdb-10.2.patch
>> > +++ b/gdb-10.2.patch
>> > @@ -221,7 +221,7 @@ exit 0
>> > warning (_("\
>> > --- gdb-10.2/gdb/main.c.orig
>> > +++ gdb-10.2/gdb/main.c
>> > -@@ -392,6 +392,14 @@ start_event_loop ()
>> > +@@ -392,6 +392,13 @@ start_event_loop ()
>> > return;
>> > }
>> >
>> > @@ -230,7 +230,6 @@ exit 0
>> > +extern "C" void main_loop(void);
>> > +extern "C" unsigned long crash_get_kaslr_offset(void);
>> > +extern "C" int console(const char *, ...);
>> > -+void crash_target_init (void);
>> > +#endif
>> > +
>> > /* Call command_loop. */
>> > @@ -316,7 +315,7 @@ exit 0
>> > }
>> > }
>> >
>> > -@@ -1242,6 +1274,16 @@ captured_main (void *data)
>> > +@@ -1242,6 +1274,14 @@ captured_main (void *data)
>> >
>> > captured_main_1 (context);
>> >
>> > @@ -324,8 +323,6 @@ exit 0
>> > + /* Relocate the vmlinux. */
>> > + objfile_rebase (symfile_objfile, crash_get_kaslr_offset());
>> > +
>> > -+ crash_target_init();
>> > -+
>> > + /* Back to crash. */
>> > + main_loop();
>> > +#endif
>> > diff --git a/gdb_interface.c b/gdb_interface.c
>> > index b14319c..03178f5 100644
>> > --- a/gdb_interface.c
>> > +++ b/gdb_interface.c
>> > @@ -3,6 +3,8 @@
>> > * Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc.
>> > * Copyright (C) 2002-2015,2018-2019 David Anderson
>> > * Copyright (C) 2002-2015,2018-2019 Red Hat, Inc. All rights reserved.
>> > + * Copyright (c) 2024 Broadcom. All Rights Reserved. The term "Broadcom"
>> > + * refers to Broadcom Inc. and/or its subsidiaries.
>> > *
>> > * This program is free software; you can redistribute it and/or modify
>> > * it under the terms of the GNU General Public License as published by
>> > @@ -711,7 +713,7 @@ static char *prohibited_list[] = {
>> > "watch", "rwatch", "awatch", "attach", "continue", "c", "fg", "detach",
>> > "finish", "handle", "interrupt", "jump", "kill", "next", "nexti",
>> > "signal", "step", "s", "stepi", "target", "until", "delete",
>> > - "clear", "disable", "enable", "condition", "ignore", "frame", "catch",
>> > + "clear", "disable", "enable", "condition", "ignore", "gcore", "catch",
>> > "tcatch", "return", "file", "exec-file", "core-file", "symbol-file",
>> > "load", "si", "ni", "shell", "sy",
>> > NULL /* must be last */
>> > @@ -877,6 +879,7 @@ gdb_readmem_callback(ulong addr, void *buf, int len, int write)
>> > switch (len)
>> > {
>> > case SIZEOF_8BIT:
>> > + fprintf(fp, "%s\n", pc->curcmd);
>> > if (STREQ(pc->curcmd, "bt")) {
>> > if (readmem(addr, memtype, buf, SIZEOF_8BIT,
>> > "gdb_readmem_callback", readflags))
>> > @@ -1063,34 +1066,52 @@ get_frame_offset(ulong pc)
>> > unsigned long crash_get_kaslr_offset(void);
>> > unsigned long crash_get_kaslr_offset(void)
>> > {
>> > - return kt->relocate * -1;
>> > + return kt->relocate * -1;
>> > }
>> >
>> > /* Callbacks for crash_target */
>> > -int crash_get_nr_cpus(void);
>> > -int crash_get_cpu_reg (int cpu, int regno, const char *regname,
>> > +int crash_get_nr_tasks(void);
>> > +void crash_get_task_info(int task_nr, unsigned long *pid, char **comm);
>> > +int crash_get_task_reg (int task_nr, int regno, const char *regname,
>> > int regsize, void *val);
>> >
>> > -int crash_get_nr_cpus(void)
>> > +int crash_get_nr_tasks(void)
>> > {
>> > - if (SADUMP_DUMPFILE())
>> > - return sadump_get_nr_cpus();
>> > - else if (DISKDUMP_DUMPFILE())
>> > - return diskdump_get_nr_cpus();
>> > - else if (KDUMP_DUMPFILE())
>> > - return kdump_get_nr_cpus();
>> > - else if (VMSS_DUMPFILE())
>> > - return vmware_vmss_get_nr_cpus();
>> > -
>> > - /* Just CPU #0 */
>> ()> - return 1;
>> > + return RUNNING_TASKS();
>> > }
>>
>> The crash_get_nr_tasks() will return a fixed number of running tasks,
>> which is the task status when crash is loading. However for live debug
>> mode, there will always be tasks exit and create, so we need to sync
>> the tasks number with the "info threads". I guess it is not an easy
>> work because that will involve:
>>
>> when crash loading:
>> for (int i = 0; i < nr_tasks; i++)
>> {
>> thread_info *thread = add_thread_silent (target, ...
>> }
>>
>> when new task create:
>> thread_info *thread = add_thread_silent (target, ...
>>
>> when task exit:
>> delete_thread(...)
>>
>> We may monitor those task create/exit events and do thread add/delete
>> in a callback function or we just always do all tasks delete/add when
>> "info thread" is invoked. But I guess none of these are as simple as
>> using crash "ps" cmd and "set <pid>", there won't be any problem.
>> Because crash "ps" can always show the current tasks status, and set
>> <pid> can switch the task context to it.
>>
>> What do you think?
>>
>> Thanks,
>> Tao Liu
>>
>> >
>> > -int crash_get_cpu_reg (int cpu, int regno, const char *regname,
>> > - int regsize, void *value)
>> > +/* Get task information by its index number in TT */
>> > +void crash_get_task_info(int task_nr, unsigned long *pid, char **comm)
>> > {
>> > - if (!machdep->get_cpu_reg)
>> > - return FALSE;
>> > - return machdep->get_cpu_reg(cpu, regno, regname, regsize, value);
>> > + int i;
>> > + struct task_context *tc;
>> > +
>> > + tc = FIRST_CONTEXT();
>> > + for (i = 0; i < RUNNING_TASKS(); i++, tc++)
>> > + if (i == task_nr) {
>> > + *pid = tc->pid;
>> > + *comm = tc->comm;
>> > + return;
>> > + }
>> > + *pid = 0;
>> > + *comm = NULL;
>> > + return;
>> > +}
>> > +
>> > +int crash_get_task_reg (int task_nr, int regno, const char *regname,
>> > + int regsize, void *value)
>> > +{
>> > + int i;
>> > + struct task_context *tc;
>> > +
>> > + if (!machdep->get_task_reg)
>> > + return FALSE;
>> > +
>> > + tc = FIRST_CONTEXT();
>> > + for (i = 0; i < RUNNING_TASKS(); i++, tc++)
>> > + if (i == task_nr) {
>> > + return machdep->get_task_reg(tc, regno, regname, regsize, value);
>> > + }
>> > + return FALSE;
>> > }
>> >
>> > diff --git a/help.c b/help.c
>> > index a9c4d30..85dbda5 100644
>> > --- a/help.c
>> > +++ b/help.c
>> > @@ -8520,6 +8520,7 @@ char *version_info[] = {
>> > "Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc.",
>> > "Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc.",
>> > "Copyright (C) 2015, 2021 VMware, Inc.",
>> > +"Copyright (C) 2024 Broadcom, Inc.",
>> > "This program is free software, covered by the GNU General Public License,",
>> > "and you are welcome to change it and/or distribute copies of it under",
>> > "certain conditions. Enter \"help copying\" to see the conditions.",
>> > diff --git a/main.c b/main.c
>> > index 0b6b927..13acd2d 100644
>> > --- a/main.c
>> > +++ b/main.c
>> > @@ -794,6 +794,7 @@ main_loop(void)
>> > } else
>> > SIGACTION(SIGINT, restart, &pc->sigaction, NULL);
>> >
>> > + crash_target_init();
>> > /*
>> > * Display system statistics and current context.
>> > */
>> > diff --git a/task.c b/task.c
>> > index ebdb5be..5d26c52 100644
>> > --- a/task.c
>> > +++ b/task.c
>> > @@ -298,6 +298,7 @@ task_init(void)
>> > tt->flags |= THREAD_INFO;
>> > }
>> >
>> > + STRUCT_SIZE_INIT(inactive_task_frame, "inactive_task_frame");
>> > MEMBER_OFFSET_INIT(task_struct_state, "task_struct", "state");
>> > MEMBER_SIZE_INIT(task_struct_state, "task_struct", "state");
>> > if (INVALID_MEMBER(task_struct_state)) {
>> > diff --git a/x86_64.c b/x86_64.c
>> > index 502817d..b6e36a5 100644
>> > --- a/x86_64.c
>> > +++ b/x86_64.c
>> > @@ -126,7 +126,7 @@ static int x86_64_get_framesize(struct bt_info *, ulong, ulong, char *);
>> > static void x86_64_framesize_debug(struct bt_info *);
>> > static void x86_64_get_active_set(void);
>> > static int x86_64_get_kvaddr_ranges(struct vaddr_range *);
>> > -static int x86_64_get_cpu_reg(int, int, const char *, int, void *);
>> > +static int x86_64_get_task_reg(struct task_context *, int, const char *, int, void *);
>> > static int x86_64_verify_paddr(uint64_t);
>> > static void GART_init(void);
>> > static void x86_64_exception_stacks_init(void);
>> > @@ -195,7 +195,7 @@ x86_64_init(int when)
>> > machdep->machspec->irq_eframe_link = UNINITIALIZED;
>> > machdep->machspec->irq_stack_gap = UNINITIALIZED;
>> > machdep->get_kvaddr_ranges = x86_64_get_kvaddr_ranges;
>> > - machdep->get_cpu_reg = x86_64_get_cpu_reg;
>> > + machdep->get_task_reg = x86_64_get_task_reg;
>> > if (machdep->cmdline_args[0])
>> > parse_cmdline_args();
>> > if ((string = pc->read_vmcoreinfo("relocate"))) {
>> > @@ -891,7 +891,7 @@ x86_64_dump_machdep_table(ulong arg)
>> > fprintf(fp, " is_page_ptr: x86_64_is_page_ptr()\n");
>> > fprintf(fp, " verify_paddr: x86_64_verify_paddr()\n");
>> > fprintf(fp, " get_kvaddr_ranges: x86_64_get_kvaddr_ranges()\n");
>> > - fprintf(fp, " get_cpu_reg: x86_64_get_cpu_reg()\n");
>> > + fprintf(fp, " get_task_reg: x86_64_get_task_reg()\n");
>> > fprintf(fp, " init_kernel_pgd: x86_64_init_kernel_pgd()\n");
>> > fprintf(fp, "clear_machdep_cache: x86_64_clear_machdep_cache()\n");
>> > fprintf(fp, " xendump_p2m_create: %s\n", PVOPS_XEN() ?
>> > @@ -6398,6 +6398,9 @@ x86_64_ORC_init(void)
>> > };
>> > struct ORC_data *orc;
>> >
>> > + MEMBER_OFFSET_INIT(inactive_task_frame_bp, "inactive_task_frame", "bp");
>> > + MEMBER_OFFSET_INIT(inactive_task_frame_ret_addr, "inactive_task_frame", "ret_addr");
>> > +
>> > if (machdep->flags & FRAMEPOINTER)
>> > return;
>> >
>> > @@ -6455,9 +6458,6 @@ x86_64_ORC_init(void)
>> > orc->__stop_orc_unwind = symbol_value("__stop_orc_unwind");
>> > orc->orc_lookup = symbol_value("orc_lookup");
>> >
>> > - MEMBER_OFFSET_INIT(inactive_task_frame_bp, "inactive_task_frame", "bp");
>> > - MEMBER_OFFSET_INIT(inactive_task_frame_ret_addr, "inactive_task_frame", "ret_addr");
>> > -
>> > orc->has_signal = MEMBER_EXISTS("orc_entry", "signal"); /* added at 6.3 */
>> > orc->has_end = MEMBER_EXISTS("orc_entry", "end"); /* removed at 6.4 */
>> >
>> > @@ -9070,14 +9070,64 @@ x86_64_get_kvaddr_ranges(struct vaddr_range *vrp)
>> > }
>> >
>> > static int
>> > -x86_64_get_cpu_reg(int cpu, int regno, const char *name,
>> > +x86_64_get_task_reg(struct task_context *tc, int regno, const char *name,
>> > int size, void *value)
>> > {
>> > if (regno >= LAST_REGNUM)
>> > return FALSE;
>> >
>> > + /*
>> > + * For inactive task, grab rip, rbp, rbx, r12, r13, r14 and r15 from
>> > + * inactive_task_frame (see __switch_to_asm). Other regs saved on
>> > + * regular frame.
>> > + */
>> > + if (!is_task_active(tc->task)) {
>> > + int frame_size = STRUCT_SIZE("inactive_task_frame");
>> > +
>> > + /* Only modern kernels supported. */
>> > + if (tt->flags & THREAD_INFO && frame_size == 7 * 8) {
>> > + ulong rsp;
>> > + int offset = 0;
>> > + switch (regno) {
>> > + case RSP_REGNUM:
>> > + readmem(tc->task + OFFSET(task_struct_thread) +
>> > + OFFSET(thread_struct_rsp), KVADDR,
>> > + &rsp, sizeof(void *),
>> > + "thread_struct rsp", FAULT_ON_ERROR);
>> > + rsp += frame_size;
>> > + memcpy(value, &rsp, size);
>> > + return TRUE;
>> > + case RIP_REGNUM:
>> > + offset += 8;
>> > + case RBP_REGNUM:
>> > + offset += 8;
>> > + case RBX_REGNUM:
>> > + offset += 8;
>> > + case R12_REGNUM:
>> > + offset += 8;
>> > + case R13_REGNUM:
>> > + offset += 8;
>> > + case R14_REGNUM:
>> > + offset += 8;
>> > + case R15_REGNUM:
>> > + readmem(tc->task + OFFSET(task_struct_thread) +
>> > + OFFSET(thread_struct_rsp), KVADDR,
>> > + &rsp, sizeof(void *),
>> > + "thread_struct rsp", FAULT_ON_ERROR);
>> > + readmem(rsp + offset, KVADDR, value, sizeof(void *),
>> > + "inactive_thread_frame saved regs", FAULT_ON_ERROR);
>> > + return TRUE;
>> > + }
>> > + }
>> > + /* TBD: older kernels support. */
>> > + return FALSE;
>> > + }
>> > +
>> > + /*
>> > + * Task is active, grab CPU's registers
>> > + */
>> > if (VMSS_DUMPFILE())
>> > - return vmware_vmss_get_cpu_reg(cpu, regno, name, size, value);
>> > + return vmware_vmss_get_cpu_reg(tc->processor, regno, name, size, value);
>> >
>> > return FALSE;
>> > }
>> > --
>> > 2.39.0
>> >
>>
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