From: Ilya Leoshkevich <iii@linux.ibm.com>

Analyzing qemu-produced core dumps of multi-threaded apps runs into:

    (gdb) info threads
      [...]
      21   Thread 0x3ff83cc0740 (LWP 9295) warning: Couldn't find general-purpose registers in core file.
    <unavailable> in ?? ()

The reason is that all pr_pid values are the same, because the same
TaskState is used for all CPUs when generating NT_PRSTATUS notes.

Fix by using TaskStates associated with individual CPUs.

Cc: qemu-stable@nongnu.org
Fixes: 243c47066253 ("linux-user/elfload: Write corefile elf header in one block")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240801202340.21845-1-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
(cherry picked from commit 5b0c2742c839376b7e03c4654914aaec6a8a7b09)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 60cf55b36c..0e00683dd2 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -4175,8 +4175,7 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr, size_t sz, off_t offset)
     bswap_phdr(phdr, 1);
 }
 
-static void fill_prstatus_note(void *data, const TaskState *ts,
-                               CPUState *cpu, int signr)
+static void fill_prstatus_note(void *data, CPUState *cpu, int signr)
 {
     /*
      * Because note memory is only aligned to 4, and target_elf_prstatus
@@ -4186,7 +4185,7 @@ static void fill_prstatus_note(void *data, const TaskState *ts,
     struct target_elf_prstatus prstatus = {
         .pr_info.si_signo = signr,
         .pr_cursig = signr,
-        .pr_pid = ts->ts_tid,
+        .pr_pid = get_task_state(cpu)->ts_tid,
         .pr_ppid = getppid(),
         .pr_pgrp = getpgrp(),
         .pr_sid = getsid(0),
@@ -4501,8 +4500,7 @@ static int elf_core_dump(int signr, const CPUArchState *env)
         CPU_FOREACH(cpu_iter) {
             dptr = fill_note(&hptr, NT_PRSTATUS, "CORE",
                              sizeof(struct target_elf_prstatus));
-            fill_prstatus_note(dptr, ts, cpu_iter,
-                               cpu_iter == cpu ? signr : 0);
+            fill_prstatus_note(dptr, cpu_iter, cpu_iter == cpu ? signr : 0);
         }
 
         if (dump_write(fd, header, data_offset) < 0) {
-- 
2.39.2