x86: Ignore trap bits on single step exceptions

When a single step exception fires, the trap bits, used to
signal hardware breakpoints, are in a random state.

These trap bits might be set if another exception will follow,
like a breakpoint in the next instruction, or a watchpoint in the
previous one. Or there can be any junk there.

So if we handle these trap bits during the single step exception,
we are going to handle an exception twice, or we are going to
handle junk.

Just ignore them in this case.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=21332

Reported-by: Michael Stefaniuc <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Maciej Rutecki <[email protected]>
Cc: Alexandre Julliard <[email protected]>
Cc: Jason Wessel <[email protected]>
Cc: All since 2.6.33.x <[email protected]>

0 files changed, 0 insertions, 0 deletions