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authorJason Wessel <jason.wessel@windriver.com>2008-09-26 10:36:41 -0500
committerJason Wessel <jason.wessel@windriver.com>2008-09-26 10:36:41 -0500
commitd7161a65341556bacb5e6654e133803f46f51063 (patch)
treeb2933dc2ce1435956c193c37fd53a3d5530fe9d7 /kernel
parent18d6522b86d21a04c8ac1ea79747e2e434a956d9 (diff)
kgdb, x86, arm, mips, powerpc: ignore user space single stepping
On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kgdb.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 949806ab67de..25d955dbb989 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -1462,7 +1462,7 @@ acquirelock:
* Get the passive CPU lock which will hold all the non-primary
* CPU in a spin state while the debugger is active
*/
- if (!kgdb_single_step || !kgdb_contthread) {
+ if (!kgdb_single_step) {
for (i = 0; i < NR_CPUS; i++)
atomic_set(&passive_cpu_wait[i], 1);
}
@@ -1475,7 +1475,7 @@ acquirelock:
#ifdef CONFIG_SMP
/* Signal the other CPUs to enter kgdb_wait() */
- if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
+ if ((!kgdb_single_step) && kgdb_do_roundup)
kgdb_roundup_cpus(flags);
#endif
@@ -1494,7 +1494,7 @@ acquirelock:
kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
kgdb_deactivate_sw_breakpoints();
kgdb_single_step = 0;
- kgdb_contthread = NULL;
+ kgdb_contthread = current;
exception_level = 0;
/* Talk to debugger with gdbserial protocol */
@@ -1508,7 +1508,7 @@ acquirelock:
kgdb_info[ks->cpu].task = NULL;
atomic_set(&cpu_in_kgdb[ks->cpu], 0);
- if (!kgdb_single_step || !kgdb_contthread) {
+ if (!kgdb_single_step) {
for (i = NR_CPUS-1; i >= 0; i--)
atomic_set(&passive_cpu_wait[i], 0);
/*