From: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
To: x86@kernel.org
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
linux-kernel@vger.kernel.org, Jamie Lokier <jamie@shareable.org>,
Mike Frysinger <vapier@gentoo.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Subject: [PATCH] x86_64: Record stack pointer before task execution begins
Date: Sun, 26 Feb 2012 21:47:55 +0530 [thread overview]
Message-ID: <1330273075-2949-1-git-send-email-siddhesh.poyarekar@gmail.com> (raw)
In-Reply-To: <CAAHN_R3zjh-xQ9yW57JhQ=AiJG+DV6D_ppveh3BvUYy8NWU3Lg@mail.gmail.com>
task->thread.usersp is unusable immediately after a binary is exec()'d
until it undergoes a context switch cycle. The start_thread() function
called during execve() saves the stack pointer into pt_regs and into
old_rsp, but fails to record it into task->thread.usersp.
Because of this, KSTK_ESP(task) returns an incorrect value for a
64-bit program until the task is switched out and back in since
switch_to swaps %rsp values in and out into task->thread.usersp.
Signed-off-by: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
---
arch/x86/kernel/process_64.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9b9fe4a..702a3b9 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -341,6 +341,7 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip,
loadsegment(es, _ds);
loadsegment(ds, _ds);
load_gs_index(0);
+ current->thread.usersp = new_sp;
regs->ip = new_ip;
regs->sp = new_sp;
percpu_write(old_rsp, new_sp);
--
1.7.7.4
next prev parent reply other threads:[~2012-02-26 16:17 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-14 12:35 [PATCH] Mark thread stack correctly in proc/<pid>/maps Siddhesh Poyarekar
2012-01-16 11:28 ` Jamie Lokier
2012-01-16 13:08 ` Siddhesh Poyarekar
2012-01-16 16:31 ` Jamie Lokier
2012-01-16 17:01 ` Siddhesh Poyarekar
2012-01-17 4:54 ` Siddhesh Poyarekar
2012-02-02 6:24 ` [RESEND][PATCH] " Siddhesh Poyarekar
2012-02-02 21:40 ` KOSAKI Motohiro
2012-02-03 7:09 ` Siddhesh Poyarekar
2012-02-03 8:01 ` KOSAKI Motohiro
2012-02-03 9:49 ` Siddhesh Poyarekar
2012-02-03 10:29 ` Mike Frysinger
2012-02-03 18:34 ` Siddhesh Poyarekar
2012-02-08 4:00 ` Siddhesh Poyarekar
2012-02-08 17:57 ` KOSAKI Motohiro
2012-02-11 10:19 ` Siddhesh Poyarekar
2012-02-11 15:03 ` [PATCH] " Siddhesh Poyarekar
2012-02-21 4:24 ` [RESEND][PATCH] " Siddhesh Poyarekar
2012-02-22 23:00 ` Andrew Morton
2012-02-23 4:03 ` [PATCH] " Siddhesh Poyarekar
2012-02-23 20:22 ` Andrew Morton
2012-02-24 13:05 ` Siddhesh Poyarekar
2012-02-26 16:17 ` Siddhesh Poyarekar [this message]
2012-02-27 6:17 ` [tip:x86/process] x86_64: Record stack pointer before task execution begins tip-bot for Siddhesh Poyarekar
2012-02-23 23:47 ` [PATCH] Mark thread stack correctly in proc/<pid>/maps Mike Frysinger
2012-02-24 5:47 ` Siddhesh Poyarekar
2012-02-24 16:12 ` Mike Frysinger
2012-02-24 18:23 ` Siddhesh Poyarekar
2012-03-01 5:20 ` [PATCH 1/2] Take rcu read lock when iterating through thread group Siddhesh Poyarekar
2012-03-01 5:20 ` [PATCH 2/2] procfs: Mark stack vma with pid of the owning task Siddhesh Poyarekar
2012-03-01 23:17 ` Andrew Morton
2012-03-01 16:51 ` [PATCH 1/2] Take rcu read lock when iterating through thread group Oleg Nesterov
2012-03-01 23:21 ` Andrew Morton
2012-03-04 20:04 ` Siddhesh Poyarekar
2012-02-23 23:17 ` [PATCH] Mark thread stack correctly in proc/<pid>/maps KOSAKI Motohiro
2012-02-24 0:49 ` KOSAKI Motohiro
2012-02-24 5:29 ` Siddhesh Poyarekar
2012-02-24 16:14 ` KOSAKI Motohiro
2012-02-24 18:58 ` Siddhesh Poyarekar
-- strict thread matches above, loose matches on Subject: below --
2012-02-28 17:04 + procfs-mark-thread-stack-correctly-in-proc-pid-maps.patch added to -mm tree Oleg Nesterov
2012-02-28 17:18 ` Siddhesh Poyarekar
2012-02-28 17:40 ` Oleg Nesterov
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