diff options
author | Oleg Nesterov <oleg@redhat.com> | 2013-07-09 01:00:56 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-09 19:33:26 +0200 |
commit | e6a7d6077106e5c72f0519ec113d986df67ee001 (patch) | |
tree | 90ff605d73b95af65700d47af64029b71c98cf5f | |
parent | ptrace: revert "Prepare to fix racy accesses on task breakpoints" (diff) | |
download | linux-e6a7d6077106e5c72f0519ec113d986df67ee001.tar.xz linux-e6a7d6077106e5c72f0519ec113d986df67ee001.zip |
ptrace/x86: simplify the "disable" logic in ptrace_write_dr7()
ptrace_write_dr7() looks unnecessarily overcomplicated. We can factor
out ptrace_modify_breakpoint() and do not do "continue" twice, just we
need to pass the proper "disabled" argument to
ptrace_modify_breakpoint().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | arch/x86/kernel/ptrace.c | 40 |
1 files changed, 15 insertions, 25 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 7a98b21945aa..0649f166d7c6 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -637,9 +637,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data) struct thread_struct *thread = &(tsk->thread); unsigned long old_dr7; int i, orig_ret = 0, rc = 0; - int enabled, second_pass = 0; - unsigned len, type; - struct perf_event *bp; + int second_pass = 0; data &= ~DR_CONTROL_RESERVED; old_dr7 = ptrace_get_dr7(thread->ptrace_bps); @@ -649,30 +647,22 @@ restore: * appropriate changes to each. */ for (i = 0; i < HBP_NUM; i++) { - enabled = decode_dr7(data, i, &len, &type); - bp = thread->ptrace_bps[i]; - - if (!enabled) { - if (bp) { - /* - * Don't unregister the breakpoints right-away, - * unless all register_user_hw_breakpoint() - * requests have succeeded. This prevents - * any window of opportunity for debug - * register grabbing by other users. - */ - if (!second_pass) - continue; - - rc = ptrace_modify_breakpoint(bp, len, type, - tsk, 1); - if (rc) - break; - } - continue; + unsigned len, type; + bool disabled = !decode_dr7(data, i, &len, &type); + struct perf_event *bp = thread->ptrace_bps[i]; + + if (disabled) { + /* + * Don't unregister the breakpoints right-away, unless + * all register_user_hw_breakpoint() requests have + * succeeded. This prevents any window of opportunity + * for debug register grabbing by other users. + */ + if (!bp || !second_pass) + continue; } - rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0); + rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled); if (rc) break; } |