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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-12-02 07:32:16 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-02 09:59:03 +0100 |
| commit | 1cedae72904b85462082dbcfd5190309ba37f8bd (patch) | |
| tree | 43c5873e8b8c1d65acd62fd5a609117fdee7c0da | |
| parent | 6b62fe019e39edfd1dbe3f224ecd0a87d9365223 (diff) | |
| download | linux-3.10-1cedae72904b85462082dbcfd5190309ba37f8bd.tar.gz linux-3.10-1cedae72904b85462082dbcfd5190309ba37f8bd.tar.bz2 linux-3.10-1cedae72904b85462082dbcfd5190309ba37f8bd.zip | |
hw-breakpoints: Keep track of user disabled breakpoints
When we disable a breakpoint through dr7, we unregister it right
away, making us lose track of its corresponding address
register value.
It means that the following sequence would be unsupported:
- set address in dr0
- enable it through dr7
- disable it through dr7
- enable it through dr7
because we lost the address register value when we disabled the
breakpoint.
Don't unregister the disabled breakpoints but rather disable
them.
Reported-by: "K.Prasad" <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1259735536-9236-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 2941b32ea66..04d182a7cfd 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -595,7 +595,7 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[]) static struct perf_event * ptrace_modify_breakpoint(struct perf_event *bp, int len, int type, - struct task_struct *tsk) + struct task_struct *tsk, int disabled) { int err; int gen_len, gen_type; @@ -616,7 +616,7 @@ ptrace_modify_breakpoint(struct perf_event *bp, int len, int type, attr = bp->attr; attr.bp_len = gen_len; attr.bp_type = gen_type; - attr.disabled = 0; + attr.disabled = disabled; return modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk); } @@ -655,13 +655,21 @@ restore: */ if (!second_pass) continue; + thread->ptrace_bps[i] = NULL; - unregister_hw_breakpoint(bp); + bp = ptrace_modify_breakpoint(bp, len, type, + tsk, 1); + if (IS_ERR(bp)) { + rc = PTR_ERR(bp); + thread->ptrace_bps[i] = NULL; + break; + } + thread->ptrace_bps[i] = bp; } continue; } - bp = ptrace_modify_breakpoint(bp, len, type, tsk); + bp = ptrace_modify_breakpoint(bp, len, type, tsk, 0); /* Incorrect bp, or we have a bug in bp API */ if (IS_ERR(bp)) { |