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| author | Brian Gerst <brgerst@gmail.com> | 2016-08-13 12:38:21 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-24 12:31:51 +0200 |
| commit | ffcb043ba524d3fbd979a9dac2c9ce8ad352000d (patch) | |
| tree | 3fe8cc4bd80dfc40819387cb966c1fdb0ef18bf9 /arch/x86/kernel | |
| parent | 616d24835eeafa8ef3466479db028abfdfc77531 (diff) | |
| download | linux-ffcb043ba524d3fbd979a9dac2c9ce8ad352000d.tar.gz linux-ffcb043ba524d3fbd979a9dac2c9ce8ad352000d.tar.bz2 linux-ffcb043ba524d3fbd979a9dac2c9ce8ad352000d.zip | |
sched/x86: Fix thread_saved_pc()
thread_saved_pc() was using a completely bogus method to get the return
address. Since switch_to() was previously inlined, there was no sane way
to know where on the stack the return address was stored. Now with the
frame of a sleeping thread well defined, this can be implemented correctly.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1471106302-10159-7-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/process.c | 11 | ||||
| -rw-r--r-- | arch/x86/kernel/process_32.c | 8 |
2 files changed, 11 insertions, 8 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 0115a4a4db96..c1fa790c81cd 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -514,6 +514,17 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) } /* + * Return saved PC of a blocked thread. + * What is this good for? it will be always the scheduler or ret_from_fork. + */ +unsigned long thread_saved_pc(struct task_struct *tsk) +{ + struct inactive_task_frame *frame = + (struct inactive_task_frame *) READ_ONCE(tsk->thread.sp); + return READ_ONCE_NOCHECK(frame->ret_addr); +} + +/* * Called from fs/proc with a reference on @p to find the function * which called into schedule(). This needs to be done carefully * because the task might wake up and we might look at a stack diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 18714a191b2d..404efdfa083b 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -55,14 +55,6 @@ #include <asm/switch_to.h> #include <asm/vm86.h> -/* - * Return saved PC of a blocked thread. - */ -unsigned long thread_saved_pc(struct task_struct *tsk) -{ - return ((unsigned long *)tsk->thread.sp)[3]; -} - void __show_regs(struct pt_regs *regs, int all) { unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; |