nptl: Add pthread_getstack_np

It returns the stack bounds of a thread following the same convention
as pthread_attr_getstack applied to the result of pthread_getattr_np.

Unlike pthread_getattr_np, it does not acquire the thread descriptor
lock nor allocates memory, which make the function async-signal-safe.

The function reports the stack set up by the kernel or by
pthread_create, the alternate signal stack is not reflected in the
result (it can be queried with sigaltstack, which is also
async-signal-safe), and stacks switched by user code, such as with
makecontext or coroutine libraries, are not tracked.

Similar interfaces are provided by Solaris (stack_getbounds), OpenBSD
(pthread_stackseg_np), and LLVM libc (pthread_getstack_np).

Checked on x86_64-linux-gnu.

NEWS

@@ -9,7 +9,9 @@ Version 2.45
 
 Major new features:
 
-  [Add new features here]
+* The function pthread_getstack_np has been added.  It returns the stack
+  bounds of a thread, like pthread_attr_getstack applied to the result of
+  pthread_getattr_np, in a async-signal-safe manner.
 
 Deprecated and removed features, and other changes affecting compatibility:
 

manual/threads.texi

@@ -1148,6 +1148,7 @@ the standard.
 * Thread CPU Affinity::			  Limiting which CPUs can run a thread.
 * Joining Threads::                       Wait for a thread to terminate.
 * Thread Names::			  Changing the name of a thread.
+* Thread Stack Bounds::			  Determining the stack of a thread.
 * Single-Threaded::                       Detecting single-threaded execution.
 * Restartable Sequences::                 Linux-specific restartable sequences
                                           integration.
@@ -1352,6 +1353,37 @@ Retrieves the name of thread @var{th}.
 @manpagefunctionstub{pthread_getname_np, 3}
 @end deftypefun
 
+@node Thread Stack Bounds
+@subsubsection Thread Stack Bounds
+
+@deftypefun int pthread_getstack_np (pthread_t @var{th}, void **@var{stackaddr}, size_t *@var{stacksize})
+@standards{GNU, pthread.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+Store the lowest usable address of the stack of thread @var{th} in
+@code{*@var{stackaddr}} and the number of bytes usable from that
+address in @code{*@var{stacksize}}, following the same convention as
+@code{pthread_attr_getstack}.  The reported size does not include the
+guard area.
+
+For the initial thread the bounds are computed from the current
+@code{RLIMIT_STACK} resource limit and the process memory map, so the
+result may change if the limit is adjusted.  On failure an error code
+is returned, for instance @code{ENOENT} when the stack bounds cannot
+be determined.
+
+Unlike @code{pthread_getattr_np}, this function does not acquire any
+lock nor allocate memory, and it is async-signal-safe.
+
+The function reports the stack set up by the kernel or by
+@code{pthread_create}.  The alternate signal stack is not reflected in
+the result, and a handler running on it still gets the bounds of the
+thread stack. The alternate stack can be queried with @code{sigaltstack}
+(@pxref{Signal Stack}), which is also async-signal-safe.
+
+Stacks switched by user code, such as with @code{makecontext} or coroutine
+libraries, are not tracked by @theglibc{} and are not reported either.
+@end deftypefun
+
 @node Single-Threaded
 @subsubsection Detecting Single-Threaded Execution
 

nptl/Makefile

@@ -118,6 +118,7 @@ routines = \
   pthread_getname \
   pthread_getschedparam \
   pthread_getspecific \
+  pthread_getstack_np \
   pthread_gettid_np \
   pthread_join \
   pthread_join_common \
@@ -328,6 +329,7 @@ tests = \
   tst-pthread-timedlock-lockloop \
   tst-pthread_exit-nothreads \
   tst-pthread_exit-nothreads-static \
+  tst-pthread_getstack_np \
   tst-pthread_gettid_np \
   tst-robust-fork \
   tst-robust12 \

nptl/Versions

@@ -383,6 +383,9 @@ libc {
   }
   GLIBC_2.43 {
   }
+  GLIBC_2.45 {
+    pthread_getstack_np;
+  }
   GLIBC_PRIVATE {
     __libc_alloca_cutoff;
     __lll_lock_wake_private;

nptl/pthread_getstack_np.c

@@ -0,0 +1,53 @@
+/* Get the stack bounds of a thread.
+   Copyright (C) 2026 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <pthreadP.h>
+
+int
+pthread_getstack_np (pthread_t threadid, void **stackaddr, size_t *stacksize)
+{
+  struct pthread *thread = (struct pthread *) threadid;
+
+  if (__glibc_likely (thread->stackblock != NULL))
+    {
+      /* As per pthread_attr_getstack, the returned size does not include the
+	 guard area.  */
+      *stacksize = thread->stackblock_size - thread->guardsize;
+#if _STACK_GROWS_DOWN
+      *stackaddr = (char *) thread->stackblock + thread->guardsize;
+#else
+      *stackaddr = thread->stackblock;
+#endif
+      return 0;
+    }
+
+  /* The initial thread stack is set up by the kernel.  */
+  void *addr;
+  size_t size;
+  int ret = __pthread_main_stack (&addr, &size);
+  if (ret != 0)
+    return ret;
+
+#if _STACK_GROWS_DOWN
+  *stackaddr = (char *) addr - size;
+#else
+  *stackaddr = addr;
+#endif
+  *stacksize = size;
+  return 0;
+}

nptl/tst-pthread_getstack_np.c

@@ -0,0 +1,285 @@
+/* Test pthread_getstack_np.
+   Copyright (C) 2026 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <unistd.h>
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/support.h>
+#include <support/xsignal.h>
+#include <support/xthread.h>
+#include <support/xunistd.h>
+
+/* The result must match what pthread_getattr_np plus pthread_attr_getstack
+   return.  */
+static void
+check_against_getattr_np (pthread_t thr)
+{
+  void *stackaddr;
+  size_t stacksize;
+  TEST_COMPARE (pthread_getstack_np (thr, &stackaddr, &stacksize), 0);
+
+  pthread_attr_t attr;
+  TEST_COMPARE (pthread_getattr_np (thr, &attr), 0);
+  void *attr_stackaddr;
+  size_t attr_stacksize;
+  TEST_COMPARE (pthread_attr_getstack (&attr, &attr_stackaddr,
+				       &attr_stacksize), 0);
+  TEST_COMPARE (pthread_attr_destroy (&attr), 0);
+
+  TEST_VERIFY (stackaddr == attr_stackaddr);
+  TEST_COMPARE (stacksize, attr_stacksize);
+}
+
+/* A local variable of the calling thread lies within the reported bounds.  */
+static void
+check_contains_local (void)
+{
+  void *stackaddr;
+  size_t stacksize;
+  TEST_COMPARE (pthread_getstack_np (pthread_self (), &stackaddr,
+				     &stacksize), 0);
+  char here;
+  TEST_VERIFY ((uintptr_t) &here >= (uintptr_t) stackaddr);
+  TEST_VERIFY ((uintptr_t) &here < (uintptr_t) stackaddr + stacksize);
+}
+
+static void *
+thread_func (void *arg)
+{
+  check_against_getattr_np (pthread_self ());
+  check_contains_local ();
+  return NULL;
+}
+
+static void *main_stackaddr;
+static size_t main_stacksize;
+
+/* Runs on the alternate signal stack, the reported bounds are still the ones
+   of the thread stack.  */
+static void
+signal_handler (int sig)
+{
+  void *stackaddr;
+  size_t stacksize;
+  TEST_COMPARE (pthread_getstack_np (pthread_self (), &stackaddr, &stacksize),
+		0);
+  TEST_VERIFY (stackaddr == main_stackaddr);
+  TEST_COMPARE (stacksize, main_stacksize);
+}
+
+/* Mount /proc so that /proc/self/maps cannot be opened, which forces the
+   AT_EXECFN fallback for the initial thread.  */
+static void
+check_proc_fallback (void *closure)
+{
+  if (!support_become_root ())
+    {
+      puts ("info: cannot become root, skipping /proc fallback check");
+      return;
+    }
+  if (!support_enter_mount_namespace ())
+    {
+      puts ("info: cannot enter mount namespace, skipping /proc fallback"
+	    " check");
+      return;
+    }
+  if (mount ("none", "/proc", "tmpfs", 0, NULL) != 0)
+    {
+      printf ("info: cannot mount tmpfs on /proc (%m), skipping /proc"
+	      " fallback check\n");
+      return;
+    }
+
+  /* The maps reader must now fail, so the fallback is exercised.  */
+  TEST_VERIFY (open64 ("/proc/self/maps", O_RDONLY) < 0);
+
+  void *stackaddr;
+  size_t stacksize;
+  int ret = pthread_getstack_np (pthread_self (), &stackaddr, &stacksize);
+
+  pthread_attr_t attr;
+  int gret = pthread_getattr_np (pthread_self (), &attr);
+  TEST_COMPARE (ret, gret);
+
+  if (ret == 0)
+    {
+      /* The fallback (downward-growing stack) reproduces the value
+	 computed from the maps, captured in the parent before the fork.  */
+      void *attr_stackaddr;
+      size_t attr_stacksize;
+      TEST_COMPARE (pthread_attr_getstack (&attr, &attr_stackaddr,
+					   &attr_stacksize), 0);
+      TEST_COMPARE (pthread_attr_destroy (&attr), 0);
+      TEST_VERIFY (stackaddr == attr_stackaddr);
+      TEST_COMPARE (stacksize, attr_stacksize);
+      TEST_VERIFY (stackaddr == main_stackaddr);
+      TEST_COMPARE (stacksize, main_stacksize);
+
+      char here;
+      TEST_VERIFY ((uintptr_t) &here >= (uintptr_t) stackaddr);
+      TEST_VERIFY ((uintptr_t) &here < (uintptr_t) stackaddr + stacksize);
+    }
+  else
+    {
+      /* Configurations without the fallback (e.g. an upward-growing
+	 stack) report the failure instead of a stack.  */
+      printf ("info: no /proc fallback in this configuration (ret %d)\n",
+	      ret);
+      TEST_COMPARE (ret, ENOENT);
+    }
+}
+
+
+/* Read the current [stack] vma from /proc/self/maps.  */
+static bool
+stack_vma (uintptr_t *lo, uintptr_t *hi)
+{
+  FILE *f = fopen ("/proc/self/maps", "r");
+  if (f == NULL)
+    return false;
+  bool found = false;
+  char line[512];
+  while (fgets (line, sizeof line, f) != NULL)
+    if (strstr (line, "[stack]") != NULL
+	&& sscanf (line, "%" SCNxPTR "-%" SCNxPTR, lo, hi) == 2)
+      {
+	found = true;
+	break;
+      }
+  fclose (f);
+  return found;
+}
+
+static __attribute__ ((noinline)) bool
+stack_grows_down_1 (uintptr_t outer)
+{
+  char inner;
+  return (uintptr_t) &inner < outer;
+}
+
+static bool
+stack_grows_down (void)
+{
+  char outer;
+  return stack_grows_down_1 ((uintptr_t) &outer);
+}
+
+/* The kernel does not grow the stack into the guard gap above the mapping
+   below it.  With a mapping planted within that distance below the current
+   vma the stack can not grow at all, so the reported lowest address must be
+   the current vma bottom rather than the end of the planted mapping.  This
+   must be the last check, since afterwards the stack can not grow.  */
+static void
+check_stack_guard_gap (void)
+{
+  if (!stack_grows_down ())
+    {
+      puts ("info: stack grows up, skipping guard gap check");
+      return;
+    }
+  uintptr_t lo, hi;
+  if (!stack_vma (&lo, &hi))
+    {
+      puts ("info: no [stack] in /proc/self/maps, skipping guard gap check");
+      return;
+    }
+
+  long pagesz = sysconf (_SC_PAGESIZE);
+  uintptr_t planted = (lo - 100 * 1024) & -(uintptr_t) pagesz;
+  void *m = mmap ((void *) planted, pagesz, PROT_READ | PROT_WRITE,
+		  MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE, -1, 0);
+  if (m == MAP_FAILED)
+    {
+      printf ("info: cannot map below the stack (%m), skipping guard gap"
+	      " check\n");
+      return;
+    }
+  TEST_VERIFY ((uintptr_t) m == planted);
+
+  void *stackaddr;
+  size_t stacksize;
+  TEST_COMPARE (pthread_getstack_np (pthread_self (), &stackaddr, &stacksize),
+		0);
+  /* The vma may only have grown down since it was read.  */
+  uintptr_t lo2, hi2;
+  TEST_VERIFY (stack_vma (&lo2, &hi2));
+  TEST_VERIFY (lo2 <= (uintptr_t) stackaddr && (uintptr_t) stackaddr <= lo);
+  TEST_VERIFY ((uintptr_t) stackaddr > planted + pagesz);
+
+  check_against_getattr_np (pthread_self ());
+}
+
+static int
+do_test (void)
+{
+  check_against_getattr_np (pthread_self ());
+  check_contains_local ();
+  TEST_COMPARE (pthread_getstack_np (pthread_self (), &main_stackaddr,
+				     &main_stacksize), 0);
+
+  /* A thread with the default stack size, queried both by itself and
+     by another thread.  */
+  {
+    pthread_t thr = xpthread_create (NULL, thread_func, NULL);
+    check_against_getattr_np (thr);
+    xpthread_join (thr);
+  }
+
+  /* A thread with a non-default stack size.  */
+  {
+    pthread_attr_t attr;
+    xpthread_attr_init (&attr);
+    xpthread_attr_setstacksize (&attr, 256 * 1024);
+    xpthread_join (xpthread_create (&attr, thread_func, NULL));
+    xpthread_attr_destroy (&attr);
+  }
+
+  /* From a signal handler running on the alternate signal stack.  */
+  {
+    struct support_stack altstack = support_stack_alloc (SIGSTKSZ);
+    stack_t ss = { .ss_sp = altstack.stack, .ss_size = altstack.size };
+    TEST_COMPARE (sigaltstack (&ss, NULL), 0);
+    xsigaction (SIGUSR1,
+		&(struct sigaction) {
+		  .sa_handler = signal_handler,
+		  .sa_flags = SA_ONSTACK },
+	        NULL);
+    xraise (SIGUSR1);
+    support_stack_free (&altstack);
+  }
+
+  /* The initial thread fallback when /proc is not accessible.  */
+  support_isolate_in_subprocess (check_proc_fallback, NULL);
+
+  check_stack_guard_gap ();
+
+  return 0;
+}
+
+#include <support/test-driver.c>

sysdeps/nptl/pthread.h

@@ -1320,6 +1320,12 @@ extern int pthread_getcpuclockid (pthread_t __thread_id,
 #ifdef __USE_GNU
 /* Return the Linux TID for THREAD_ID.  Returns -1 on failure.  */
 extern pid_t pthread_gettid_np (pthread_t __thread_id);
+
+/* Store the lowest usable address of the stack of THREAD_ID in *STACKADDR and
+   the number of usable bytes from that address in *STACKSIZE.  */
+extern int pthread_getstack_np (pthread_t __thread_id,
+				void **__stackaddr, size_t *__stacksize)
+     __THROW __nonnull ((2, 3));
 #endif
 
 

sysdeps/unix/sysv/linux/Makefile

@@ -563,6 +563,8 @@ sysdep_routines += \
   spawnattr_setcgroup_np \
   # sysdep_routines
 
+CFLAGS-procutils.c += -fexceptions -fasynchronous-unwind-tables
+
 tests += \
   tst-affinity \
   tst-affinity-pid \

sysdeps/unix/sysv/linux/aarch64/libc.abilist

@@ -2775,3 +2775,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/alpha/libc.abilist

@@ -3122,6 +3122,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/arc/libc.abilist

@@ -2536,3 +2536,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/arm/be/libc.abilist

@@ -2828,6 +2828,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/arm/le/libc.abilist

@@ -2825,6 +2825,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/csky/libc.abilist

@@ -2812,3 +2812,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/hppa/libc.abilist

@@ -2849,6 +2849,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/i386/libc.abilist

@@ -3032,6 +3032,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/loongarch/ilp32/libc.abilist

@@ -2287,3 +2287,4 @@ GLIBC_2.44 wprintf F
 GLIBC_2.44 write F
 GLIBC_2.44 writev F
 GLIBC_2.44 wscanf F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist

@@ -2296,3 +2296,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist

@@ -2808,6 +2808,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist

@@ -2975,6 +2975,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/microblaze/be/libc.abilist

@@ -2861,3 +2861,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/microblaze/le/libc.abilist

@@ -2858,3 +2858,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist

@@ -2938,6 +2938,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist

@@ -2936,6 +2936,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist

@@ -2944,6 +2944,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist

@@ -2846,6 +2846,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/or1k/libc.abilist

@@ -2286,3 +2286,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist

@@ -3165,6 +3165,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist

@@ -3210,6 +3210,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist

@@ -2919,6 +2919,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist

@@ -2995,3 +2995,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/procutils.c

@@ -16,6 +16,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <libc-lock.h>
 #include <not-cancel.h>
 #include <procutils.h>
 #include <stdbool.h>
@@ -109,6 +110,12 @@ next_line (struct line_reader *lr, char **r)
     }
 }
 
+static void
+close_handler (void *arg)
+{
+  __close_nocancel_nostatus (*(int *) arg);
+}
+
 enum procutils_read_result_t
 __libc_procutils_read_file (const char *filename, char *buffer,
 			    size_t buffer_size, procutils_closure_t closure,
@@ -127,7 +134,11 @@ __libc_procutils_read_file (const char *filename, char *buffer,
   if (lr.fd == -1)
     return procutils_read_error;
 
+  /* The cleanup handler is required to avoid leaking the descriptor if
+     the thread is asynchronously canceled.  */
   enum next_line_result_t r;
+  __libc_cleanup_push (close_handler, &lr.fd);
+
   char *line;
   while ((r = next_line (&lr, &line)) == next_line_ok)
     if (closure (line, arg) != 0)
@@ -135,6 +146,8 @@ __libc_procutils_read_file (const char *filename, char *buffer,
 
   __close_nocancel_nostatus (lr.fd);
 
+  __libc_cleanup_pop (0);
+
   if (r == next_line_error)
     return procutils_read_error;
   return r == next_line_ok ? procutils_read_stop : procutils_read_eof;

sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist

@@ -2539,3 +2539,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist

@@ -2739,3 +2739,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F

sysdeps/unix/sysv/linux/s390/libc.abilist

@@ -2956,6 +2956,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/sh/be/libc.abilist

@@ -2855,6 +2855,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/sh/le/libc.abilist

@@ -2852,6 +2852,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist

@@ -3186,6 +3186,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist

@@ -2822,6 +2822,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/x86_64/64/libc.abilist

@@ -2771,6 +2771,7 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F
 GLIBC_2.5 __readlinkat_chk F
 GLIBC_2.5 inet6_opt_append F
 GLIBC_2.5 inet6_opt_find F

sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist

@@ -2790,3 +2790,4 @@ GLIBC_2.43 memset_explicit F
 GLIBC_2.43 mseal F
 GLIBC_2.43 openat2 F
 GLIBC_2.43 umaxabs F
+GLIBC_2.45 pthread_getstack_np F