diff options
| author | Daniel Glöckner <dg@emlix.com> | 2009-03-04 19:42:27 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-04 20:33:16 +0100 |
| commit | ab9e18587f4cdb5f3fb3854c732f27a36f98e8f6 (patch) | |
| tree | b8d77d5fbdbdf919e4c0134762ff36ef11626802 /arch/x86/kernel/i387.c | |
| parent | dd39ecf522ba86c70809715af46e6557f6491131 (diff) | |
| download | linux-ab9e18587f4cdb5f3fb3854c732f27a36f98e8f6.tar.bz2 | |
x86, math-emu: fix init_fpu for task != current
Impact: fix math-emu related crash while using GDB/ptrace
init_fpu() calls finit to initialize a task's xstate, while finit always
works on the current task. If we use PTRACE_GETFPREGS on another
process and both processes did not already use floating point, we get
a null pointer exception in finit.
This patch creates a new function finit_task that takes a task_struct
parameter. finit becomes a wrapper that simply calls finit_task with
current. On the plus side this avoids many calls to get_current which
would each resolve to an inline assembler mov instruction.
An empty finit_task has been added to i387.h to avoid linker errors in
case the compiler still emits the call in init_fpu when
CONFIG_MATH_EMULATION is not defined.
The declaration of finit in i387.h has been removed as the remaining
code using this function gets its prototype from fpu_proto.h.
Signed-off-by: Daniel Glöckner <dg@emlix.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Bill Metzenthen <billm@melbpc.org.au>
LKML-Reference: <E1Lew31-0004il-Fg@mailer.emlix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/i387.c')
| -rw-r--r-- | arch/x86/kernel/i387.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index b0f61f0dcd0a..f2f8540a7f3d 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -136,7 +136,7 @@ int init_fpu(struct task_struct *tsk) #ifdef CONFIG_X86_32 if (!HAVE_HWFP) { memset(tsk->thread.xstate, 0, xstate_size); - finit(); + finit_task(tsk); set_stopped_child_used_math(tsk); return 0; } |