+++ /dev/null
-From 34441427aab4bdb3069a4ffcda69a99357abcb2e Mon Sep 17 00:00:00 2001
-From: Robin Holt <holt@sgi.com>
-Date: Tue, 11 May 2010 14:06:46 -0700
-Subject: revert "procfs: provide stack information for threads" and its fixup commits
-
-From: Robin Holt <holt@sgi.com>
-
-commit 34441427aab4bdb3069a4ffcda69a99357abcb2e upstream.
-
-Originally, commit d899bf7b ("procfs: provide stack information for
-threads") attempted to introduce a new feature for showing where the
-threadstack was located and how many pages are being utilized by the
-stack.
-
-Commit c44972f1 ("procfs: disable per-task stack usage on NOMMU") was
-applied to fix the NO_MMU case.
-
-Commit 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on
-64-bit") was applied to fix a bug in ia32 executables being loaded.
-
-Commit 9ebd4eba7 ("procfs: fix /proc/<pid>/stat stack pointer for kernel
-threads") was applied to fix a bug which had kernel threads printing a
-userland stack address.
-
-Commit 1306d603f ('proc: partially revert "procfs: provide stack
-information for threads"') was then applied to revert the stack pages
-being used to solve a significant performance regression.
-
-This patch nearly undoes the effect of all these patches.
-
-The reason for reverting these is it provides an unusable value in
-field 28. For x86_64, a fork will result in the task->stack_start
-value being updated to the current user top of stack and not the stack
-start address. This unpredictability of the stack_start value makes
-it worthless. That includes the intended use of showing how much stack
-space a thread has.
-
-Other architectures will get different values. As an example, ia64
-gets 0. The do_fork() and copy_process() functions appear to treat the
-stack_start and stack_size parameters as architecture specific.
-
-I only partially reverted c44972f1 ("procfs: disable per-task stack usage
-on NOMMU") . If I had completely reverted it, I would have had to change
-mm/Makefile only build pagewalk.o when CONFIG_PROC_PAGE_MONITOR is
-configured. Since I could not test the builds without significant effort,
-I decided to not change mm/Makefile.
-
-I only partially reverted 89240ba0 ("x86, fs: Fix x86 procfs stack
-information for threads on 64-bit") . I left the KSTK_ESP() change in
-place as that seemed worthwhile.
-
-Signed-off-by: Robin Holt <holt@sgi.com>
-Cc: Stefani Seibold <stefani@seibold.net>
-Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
-Cc: Michal Simek <monstr@monstr.eu>
-Cc: Ingo Molnar <mingo@elte.hu>
-Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-
----
- Documentation/filesystems/proc.txt | 3 +--
- fs/compat.c | 2 --
- fs/exec.c | 2 --
- fs/proc/array.c | 3 +--
- fs/proc/task_mmu.c | 19 -------------------
- include/linux/sched.h | 1 -
- kernel/fork.c | 2 --
- 7 files changed, 2 insertions(+), 30 deletions(-)
-
---- a/Documentation/filesystems/proc.txt
-+++ b/Documentation/filesystems/proc.txt
-@@ -309,7 +309,7 @@ address perms offset dev in
- 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test
- 0804a000-0806b000 rw-p 00000000 00:00 0 [heap]
- a7cb1000-a7cb2000 ---p 00000000 00:00 0
--a7cb2000-a7eb2000 rw-p 00000000 00:00 0 [threadstack:001ff4b4]
-+a7cb2000-a7eb2000 rw-p 00000000 00:00 0
- a7eb2000-a7eb3000 ---p 00000000 00:00 0
- a7eb3000-a7ed5000 rw-p 00000000 00:00 0
- a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6
-@@ -345,7 +345,6 @@ is not associated with a file:
- [stack] = the stack of the main process
- [vdso] = the "virtual dynamic shared object",
- the kernel system call handler
-- [threadstack:xxxxxxxx] = the stack of the thread, xxxxxxxx is the stack size
-
- or if empty, the mapping is anonymous.
-
---- a/fs/compat.c
-+++ b/fs/compat.c
-@@ -1532,8 +1532,6 @@ int compat_do_execve(char * filename,
- if (retval < 0)
- goto out;
-
-- current->stack_start = current->mm->start_stack;
--
- /* execve succeeded */
- current->fs->in_exec = 0;
- current->in_execve = 0;
---- a/fs/exec.c
-+++ b/fs/exec.c
-@@ -1379,8 +1379,6 @@ int do_execve(char * filename,
- if (retval < 0)
- goto out;
-
-- current->stack_start = current->mm->start_stack;
--
- /* execve succeeded */
- current->fs->in_exec = 0;
- current->in_execve = 0;
---- a/fs/proc/array.c
-+++ b/fs/proc/array.c
-@@ -82,7 +82,6 @@
- #include <linux/pid_namespace.h>
- #include <linux/ptrace.h>
- #include <linux/tracehook.h>
--#include <linux/swapops.h>
-
- #include <asm/pgtable.h>
- #include <asm/processor.h>
-@@ -571,7 +570,7 @@ static int do_task_stat(struct seq_file
- rsslim,
- mm ? mm->start_code : 0,
- mm ? mm->end_code : 0,
-- (permitted && mm) ? task->stack_start : 0,
-+ (permitted && mm) ? mm->start_stack : 0,
- esp,
- eip,
- /* The signal information here is obsolete.
---- a/fs/proc/task_mmu.c
-+++ b/fs/proc/task_mmu.c
-@@ -243,25 +243,6 @@ static void show_map_vma(struct seq_file
- } else if (vma->vm_start <= mm->start_stack &&
- vma->vm_end >= mm->start_stack) {
- name = "[stack]";
-- } else {
-- unsigned long stack_start;
-- struct proc_maps_private *pmp;
--
-- pmp = m->private;
-- stack_start = pmp->task->stack_start;
--
-- if (vma->vm_start <= stack_start &&
-- vma->vm_end >= stack_start) {
-- pad_len_spaces(m, len);
-- seq_printf(m,
-- "[threadstack:%08lx]",
--#ifdef CONFIG_STACK_GROWSUP
-- vma->vm_end - stack_start
--#else
-- stack_start - vma->vm_start
--#endif
-- );
-- }
- }
- } else {
- name = "[vdso]";
---- a/include/linux/sched.h
-+++ b/include/linux/sched.h
-@@ -1541,7 +1541,6 @@ struct task_struct {
- /* bitmask of trace recursion */
- unsigned long trace_recursion;
- #endif /* CONFIG_TRACING */
-- unsigned long stack_start;
- };
-
- /* Future-safe accessor for struct task_struct's cpus_allowed. */
---- a/kernel/fork.c
-+++ b/kernel/fork.c
-@@ -1123,8 +1123,6 @@ static struct task_struct *copy_process(
-
- p->bts = NULL;
-
-- p->stack_start = stack_start;
--
- /* Perform scheduler related setup. Assign this task to a CPU. */
- sched_fork(p, clone_flags);
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
