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authorFrederic Weisbecker <fweisbec@gmail.com>2010-02-18 16:00:59 +0100
committerFrederic Weisbecker <fweisbec@gmail.com>2010-02-19 18:35:14 +0100
commit84d710926797a6e317e7e94654a3ccd771cfd8a3 (patch)
tree81dbf3f67f75111c00d32f22bd62c251ffdeef91 /arch
parent6f93d0a7c83772997b81c30d6f519a9a5dbab6a9 (diff)
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hw-breakpoints: Accept breakpoints on NULL address
Before we had a generic breakpoint API, ptrace was accepting breakpoints on NULL address in x86. The new API refuse them, without given strong reasons. We need to follow the previous behaviour as some userspace apps like Wine need such NULL breakpoints to ensure old emulated software protections are still working. This fixes a 2.6.32 - 2.6.33-x ptrace regression. Reported-and-tested-by: Michael Stefaniuc <mstefani@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: K.Prasad <prasad@linux.vnet.ibm.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Maneesh Soni <maneesh@linux.vnet.ibm.com> Cc: Alexandre Julliard <julliard@winehq.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/hw_breakpoint.c30
1 files changed, 7 insertions, 23 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index 05d5fec64a9..bb6006e3e29 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -212,25 +212,6 @@ static int arch_check_va_in_kernelspace(unsigned long va, u8 hbp_len)
return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
}
-/*
- * Store a breakpoint's encoded address, length, and type.
- */
-static int arch_store_info(struct perf_event *bp)
-{
- struct arch_hw_breakpoint *info = counter_arch_bp(bp);
- /*
- * For kernel-addresses, either the address or symbol name can be
- * specified.
- */
- if (info->name)
- info->address = (unsigned long)
- kallsyms_lookup_name(info->name);
- if (info->address)
- return 0;
-
- return -EINVAL;
-}
-
int arch_bp_generic_fields(int x86_len, int x86_type,
int *gen_len, int *gen_type)
{
@@ -362,10 +343,13 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp,
return ret;
}
- ret = arch_store_info(bp);
-
- if (ret < 0)
- return ret;
+ /*
+ * For kernel-addresses, either the address or symbol name can be
+ * specified.
+ */
+ if (info->name)
+ info->address = (unsigned long)
+ kallsyms_lookup_name(info->name);
/*
* Check that the low-order bits of the address are appropriate
* for the alignment implied by len.