From: Masayoshi Mizuma <m mizuma jp fujitsu com>

On 4.19 and newer kernel, gcore command fails as following:

===========================================================

    gcore: invalid structure size: pid_link

           FILE: libgcore/gcore_coredump_table.c  LINE: 423  FUNCTION: pid_alive()

    [./crash] error trace: 7f4a7a6762b8 => 7f4a7a676e0f => 53b391 => 53b316

      53b316: SIZE_verify.part.31+70

      53b391: SIZE_verify+49

    gcore: invalid structure size: pid_link

           FILE: libgcore/gcore_coredump_table.c  LINE: 423  FUNCTION: pid_alive()

    Failed.

===========================================================

That is because struct pid_link is removed and struct pid array is added to

struct signal_struct by commit 2c4704756cab ("pids: Move the pgrp and session

pid pointers from task_struct to signal_struct").

Get the pointer of struct pid from task_struct->thread_pid or

signal_struct->pids[] to fix the failure.

Signed-off-by: Masayoshi Mizuma <m mizuma jp fujitsu com>

---

 gcore.c                         |  4 +++

 libgcore/gcore_coredump_table.c | 48 +++++++++++++++++++++++++++------

 libgcore/gcore_defs.h           |  2 ++

 3 files changed, 46 insertions(+), 8 deletions(-)

--- a/gcore.c

+++ b/gcore.c

@@ -505,6 +505,10 @@ static void gcore_offset_table_init(void

 		GCORE_ANON_MEMBER_OFFSET_INIT(thread_struct_fpsimd_state, "thread_struct", "uw.fpsimd_state");

 		GCORE_ANON_MEMBER_OFFSET_INIT(thread_struct_tp_value, "thread_struct", "uw.tp_value");

 	}

+	if (MEMBER_EXISTS("task_struct", "thread_pid"))

+		GCORE_MEMBER_OFFSET_INIT(task_struct_thread_pid, "task_struct", "thread_pid");

+	if (MEMBER_EXISTS("signal_struct", "pids"))

+		GCORE_MEMBER_OFFSET_INIT(signal_struct_pids, "signal_struct", "pids");

 }

 static void gcore_size_table_init(void)

diff --git a/libgcore/gcore_coredump_table.c b/libgcore/gcore_coredump_table.c

index a073591..4cf9c38 100644

--- a/libgcore/gcore_coredump_table.c

+++ b/libgcore/gcore_coredump_table.c

@@ -224,7 +224,7 @@ __task_pid_nr_ns(ulong task, enum pid_type type)

 		sizeof(ns), "__task_pid_nr_ns: ns", gcore_verbose_error_handle());

 	if (pid_alive(task)) {

-		ulong pids_type_pid;

+		ulong pids_type_pid, signal;

                 if (type != PIDTYPE_PID)

 			readmem(task + MEMBER_OFFSET("task_struct",

@@ -233,10 +233,34 @@ __task_pid_nr_ns(ulong task, enum pid_type type)

 				"__task_pid_nr_ns: group_leader",

 				gcore_verbose_error_handle());

-		readmem(task + OFFSET(task_struct_pids) + type * SIZE(pid_link)

-			+ OFFSET(pid_link_pid), KVADDR, &pids_type_pid,

-			sizeof(pids_type_pid),

-			"__task_pid_nr_ns: pids_type_pid", gcore_verbose_error_handle());

+		if (VALID_MEMBER(task_struct_pids))

+			readmem(task + OFFSET(task_struct_pids) +

+				type * SIZE(pid_link) + OFFSET(pid_link_pid),

+				KVADDR, &pids_type_pid,

+				sizeof(pids_type_pid),

+				"__task_pid_nr_ns: pids_type_pid",

+				gcore_verbose_error_handle());

+		else

+			if (type == PIDTYPE_PID)

+				readmem(task + GCORE_OFFSET(task_struct_thread_pid),

+					KVADDR, &pids_type_pid,

+					sizeof(pids_type_pid),

+					"__task_pid_nr_ns: pids_type_pid",

+					gcore_verbose_error_handle());

+			else {

+				readmem(task + OFFSET(task_struct_signal),

+					KVADDR, &signal,

+					sizeof(signal),

+					"__task_pid_nr_ns: signal",

+					gcore_verbose_error_handle());

+

+				readmem(signal + GCORE_OFFSET(signal_struct_pids) +

+					type * sizeof(void *),

+					KVADDR, &pids_type_pid,

+					sizeof(pids_type_pid),

+					"__task_pid_nr_ns: pids_type_pid",

+					gcore_verbose_error_handle());

+			}

 		nr = pid_nr_ns(pids_type_pid, ns);

         }

@@ -420,9 +444,17 @@ pid_alive(ulong task)

 {

 	pid_t pid;

-	readmem(task + OFFSET(task_struct_pids) + PIDTYPE_PID * SIZE(pid_link)

-		+ OFFSET(pid_link_pid), KVADDR, &pid, sizeof(pid), "pid_alive",

-		gcore_verbose_error_handle());

+	if (VALID_MEMBER(task_struct_pids))

+		readmem(task + OFFSET(task_struct_pids) +

+			PIDTYPE_PID * SIZE(pid_link) + OFFSET(pid_link_pid),

+			KVADDR, &pid, sizeof(pid),

+			"pid_alive",

+			gcore_verbose_error_handle());

+	else

+		readmem(task + GCORE_OFFSET(task_struct_thread_pid),

+			KVADDR, &pid, sizeof(pid),

+			"task_struct.thread_pid",

+			gcore_verbose_error_handle());

         return !!pid;

 }

diff --git a/libgcore/gcore_defs.h b/libgcore/gcore_defs.h

index 18c4c2c..3c839f9 100644

--- a/libgcore/gcore_defs.h

+++ b/libgcore/gcore_defs.h

@@ -1077,6 +1077,7 @@ struct gcore_offset_table

 	long sched_entity_sum_exec_runtime;

 	long signal_struct_cutime;

 	long signal_struct_pgrp;

+	long signal_struct_pids;

 	long signal_struct_session;

 	long signal_struct_stime;

 	long signal_struct_sum_sched_runtime;

@@ -1090,6 +1091,7 @@ struct gcore_offset_table

 	long task_struct_static_prio;

 	long task_struct_uid;

 	long task_struct_used_math;

+	long task_struct_thread_pid;

 	long thread_info_status;

 	long thread_info_fpstate;

 	long thread_info_vfpstate;

-- 

2.18.1

--- a/gcore.mk

+++ b/gcore.mk

@@ -12,9 +12,9 @@

 # GNU General Public License for more details.

 #

-VERSION=1.5.0

-DATE=30 Nov 2018

-PERIOD=2010, 2011, 2012, 2013, 2014, 2016, 2017, 2018

+VERSION=1.5.1

+DATE=25 Jun 2019

+PERIOD=2010, 2011, 2012, 2013, 2014, 2016, 2017, 2018, 2019

 ARCH=UNSUPPORTED