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x86, bts: add fork and exit handling

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Impact: introduce new ptrace facility

Add arch_ptrace_untrace() function that is called when the tracer
detaches (either voluntarily or when the tracing task dies);
ptrace_disable() is only called on a voluntary detach.

Add ptrace_fork() and arch_ptrace_fork(). They are called when a
traced task is forked.

Clear DS and BTS related fields on fork.

Release DS resources and reclaim memory in ptrace_untrace(). This
releases resources already when the tracing task dies. We used to do
that when the traced task dies.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Markus Metzger
2008-12-19 15:10:24 +01:00
committed by Ingo Molnar
parent 30cd324e97
commit bf53de907d
9 changed files with 119 additions and 30 deletions
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18
arch/x86/kernel/process_64.c
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@@ -53,6 +53,7 @@
#include <asm/ia32.h>
#include <asm/idle.h>
#include <asm/syscalls.h>
#include <asm/ds.h>
asmlinkage extern void ret_from_fork(void);
@@ -236,17 +237,8 @@ void exit_thread(void)
t->io_bitmap_max = 0;
put_cpu();
}
#ifdef CONFIG_X86_DS
/* Free any BTS tracers that have not been properly released. */
if (unlikely(current->bts)) {
ds_release_bts(current->bts);
current->bts = NULL;
kfree(current->bts_buffer);
current->bts_buffer = NULL;
current->bts_size = 0;
}
#endif /* CONFIG_X86_DS */
ds_exit_thread(current);
}
void flush_thread(void)
@@ -376,6 +368,12 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
if (err)
goto out;
}
ds_copy_thread(p, me);
clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
p->thread.debugctlmsr = 0;
err = 0;
out:
if (err && p->thread.io_bitmap_ptr) {