On Mon, Mar 24, 2008 at 11:43:08AM +0100, Bastian Blank wrote:
> On Mon, Mar 24, 2008 at 10:33:52AM +0100, Aurelien Jarno wrote:
> > Please find below a patch for 2.6.18, which should also apply to all
> > pre- x86/x86-64 merge 2.6 kernels.
>
> No, it does not.
>
Oops I've sent the wrong patch. Please find the correct patch below:
commit 9b25e7f72161a95d7e255b0277c951f7f9aee59f
Author: Aurelien Jarno <[EMAIL PROTECTED]>
Date: Mon Mar 24 09:43:27 2008 +0100
x86: Clear DF before calling signal handler
The Linux kernel currently does not clear the direction flag before
calling a signal handler, whereas the x86/x86-64 ABI requires that.
This become a real problem with gcc version 4.3, which assumes that
the direction flag is correctly cleared at the entry of a function.
This patches changes the setup_frame() functions to clear the
direction before entering the signal handler.
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c
index 43002cf..2dea594 100644
--- a/arch/i386/kernel/signal.c
+++ b/arch/i386/kernel/signal.c
@@ -391,7 +391,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
* The tracer may want to single-step inside the
* handler too.
*/
- regs->eflags &= ~TF_MASK;
+ regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
@@ -485,7 +485,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka,
siginfo_t *info,
* The tracer may want to single-step inside the
* handler too.
*/
- regs->eflags &= ~TF_MASK;
+ regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
diff --git a/arch/x86_64/ia32/ia32_signal.c b/arch/x86_64/ia32/ia32_signal.c
index 25e5ca2..97febdf 100644
--- a/arch/x86_64/ia32/ia32_signal.c
+++ b/arch/x86_64/ia32/ia32_signal.c
@@ -499,7 +499,7 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
regs->ss = __USER32_DS;
set_fs(USER_DS);
- regs->eflags &= ~TF_MASK;
+ regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
@@ -595,7 +595,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka,
siginfo_t *info,
regs->ss = __USER32_DS;
set_fs(USER_DS);
- regs->eflags &= ~TF_MASK;
+ regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c
index 2816117..a4baa0f 100644
--- a/arch/x86_64/kernel/signal.c
+++ b/arch/x86_64/kernel/signal.c
@@ -333,7 +333,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka,
siginfo_t *info,
see include/asm-x86_64/uaccess.h for details. */
set_fs(USER_DS);
- regs->eflags &= ~TF_MASK;
+ regs->eflags &= ~(TF_MASK | X86_EFLAGS_DF);
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
#ifdef DEBUG_SIG
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' [EMAIL PROTECTED] | [EMAIL PROTECTED]
`- people.debian.org/~aurel32 | www.aurel32.net
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