Commit-ID: a8424003679e90b9952e20adcd1ff1560d9dd3e9
Gitweb: http://git.kernel.org/tip/a8424003679e90b9952e20adcd1ff1560d9dd3e9
Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
AuthorDate: Thu, 11 Jun 2015 12:34:00 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 12 Jun 2015 10:48:12 +0200
x86/fpu: Fix double-increment in setup_xstate_features()
I noticed that my MPX tracepoints were producing garbage for the
lower and upper bounds:
mpx_bounds_register_exception: address referenced: 0x00007fffffffccb7 bounds: lower: 0x0 ~upper: 0xffffffffffffffff
mpx_bounds_register_exception: address referenced: 0x00007fffffffccbf bounds: lower: 0x0 ~upper: 0xffffffffffffffff
This is, of course, bogus because 0x00007fffffffccbf is *within*
the bounds. I assumed that my instruction decoder was bad and
went looking at it. But I eventually realized that I was
getting a '0' offset back from xstate_offsets[BNDREGS].
It was being skipped in the initialization, which is obviously
bogus, so remove the extra leaf++.
This also goes an initializes xstate_offsets/sizes[] to -1 so
so that bugs like this will oops instead of silently failing
in interesting ways.
This was introduced by:
39f1acd ("x86/fpu/xstate: Don't assume the first zero xfeatures zero bit means the end")
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: dave@xxxxxxxx
Link: http://lkml.kernel.org/r/20150611193400.2E0B00DB@xxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/fpu/xstate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 49d0d9b..62fc001 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -31,7 +31,8 @@ static const char *xfeature_names[] =
*/
u64 xfeatures_mask __read_mostly;
-static unsigned int xstate_offsets[XFEATURES_NR_MAX], xstate_sizes[XFEATURES_NR_MAX];
+static unsigned int xstate_offsets[XFEATURES_NR_MAX] = { [ 0 ... XFEATURES_NR_MAX - 1] = -1};
+static unsigned int xstate_sizes[XFEATURES_NR_MAX] = { [ 0 ... XFEATURES_NR_MAX - 1] = -1};
static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
/* The number of supported xfeatures in xfeatures_mask: */
@@ -187,7 +188,6 @@ static void __init setup_xstate_features(void)
xstate_sizes[leaf] = eax;
printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %04x, xstate_sizes[%d]: %04x\n", leaf, ebx, leaf, eax);
- leaf++;
}
}
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|