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authorOleg Nesterov <oleg@redhat.com>2013-07-08 16:01:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-09 10:33:26 -0700
commitb87a95ad609619482df0690320d5ace33ace8e7a (patch)
tree8b82e73b6daa22d4cfeac8d217401906502c1c6f /arch
parent9afe33ada275f2413dfeae27cc58fbb27474ac72 (diff)
ptrace/x86: ptrace_write_dr7() should create bp if !disabled
Commit 24f1e32c60c4 ("hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events") introduced the minor regression. Before this commit PTRACE_POKEUSER DR7, enableDR0 PTRACE_POKEUSER DR0, address was perfectly valid, now PTRACE_POKEUSER(DR7) fails if DR0 was not previously initialized by PTRACE_POKEUSER(DR0). Change ptrace_write_dr7() to do ptrace_register_breakpoint(addr => 0) if !bp && !disabled. This fixes watchpoint-zeroaddr from ptrace-tests, see https://bugzilla.redhat.com/show_bug.cgi?id=660204. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@kernel.org> 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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/ptrace.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 052636801b4..5c387b3dce3 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -670,13 +670,16 @@ restore:
if (!bp) {
if (disabled)
continue;
- /*
- * We should have at least an inactive breakpoint at
- * this slot. It means the user is writing dr7 without
- * having written the address register first.
- */
- rc = -EINVAL;
- break;
+
+ bp = ptrace_register_breakpoint(tsk,
+ len, type, 0, disabled);
+ if (IS_ERR(bp)) {
+ rc = PTR_ERR(bp);
+ break;
+ }
+
+ thread->ptrace_bps[i] = bp;
+ continue;
}
rc = ptrace_modify_breakpoint(bp, len, type, disabled);