diff options
author | Steven Rostedt <srostedt@redhat.com> | 2012-02-01 09:59:24 -0500 |
---|---|---|
committer | Steven Rostedt <rostedt@goodmis.org> | 2013-08-06 21:54:33 -0400 |
commit | fb40d7a8994a3cc7a1e1c1f3258ea8662a366916 (patch) | |
tree | a1d3664ba12dafc4029b6fc3aff2adf767a4fb83 | |
parent | 9c85f3bdf400665eecf62658a9106501f6a77a13 (diff) |
x86/jump-label: Show where and what was wrong on errors
When modifying text sections for jump labels, a paranoid check is
performed. If the check fails, the system "bugs". But why it failed
is not shown.
The BUG_ON()s in the jump label update code is replaced with bug_at(ip).
This is a function that will show what pointer failed, and what was
at the location of the failure that made jump label panic.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r-- | arch/x86/kernel/jump_label.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index 24cf2b25ce73..912a52812916 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c | |||
@@ -24,6 +24,18 @@ union jump_code_union { | |||
24 | } __attribute__((packed)); | 24 | } __attribute__((packed)); |
25 | }; | 25 | }; |
26 | 26 | ||
27 | static void bug_at(unsigned char *ip, int line) | ||
28 | { | ||
29 | /* | ||
30 | * The location is not an op that we were expecting. | ||
31 | * Something went wrong. Crash the box, as something could be | ||
32 | * corrupting the kernel. | ||
33 | */ | ||
34 | pr_warning("Unexpected op at %pS [%p] (%02x %02x %02x %02x %02x) %s:%d\n", | ||
35 | ip, ip, ip[0], ip[1], ip[2], ip[3], ip[4], __FILE__, line); | ||
36 | BUG(); | ||
37 | } | ||
38 | |||
27 | static void __jump_label_transform(struct jump_entry *entry, | 39 | static void __jump_label_transform(struct jump_entry *entry, |
28 | enum jump_label_type type, | 40 | enum jump_label_type type, |
29 | void *(*poker)(void *, const void *, size_t), | 41 | void *(*poker)(void *, const void *, size_t), |
@@ -37,7 +49,8 @@ static void __jump_label_transform(struct jump_entry *entry, | |||
37 | * We are enabling this jump label. If it is not a nop | 49 | * We are enabling this jump label. If it is not a nop |
38 | * then something must have gone wrong. | 50 | * then something must have gone wrong. |
39 | */ | 51 | */ |
40 | BUG_ON(memcmp((void *)entry->code, ideal_nop, 5) != 0); | 52 | if (unlikely(memcmp((void *)entry->code, ideal_nop, 5) != 0)) |
53 | bug_at((void *)entry->code, __LINE__); | ||
41 | 54 | ||
42 | code.jump = 0xe9; | 55 | code.jump = 0xe9; |
43 | code.offset = entry->target - | 56 | code.offset = entry->target - |
@@ -51,12 +64,14 @@ static void __jump_label_transform(struct jump_entry *entry, | |||
51 | */ | 64 | */ |
52 | if (init) { | 65 | if (init) { |
53 | const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; | 66 | const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; |
54 | BUG_ON(memcmp((void *)entry->code, default_nop, 5) != 0); | 67 | if (unlikely(memcmp((void *)entry->code, default_nop, 5) != 0)) |
68 | bug_at((void *)entry->code, __LINE__); | ||
55 | } else { | 69 | } else { |
56 | code.jump = 0xe9; | 70 | code.jump = 0xe9; |
57 | code.offset = entry->target - | 71 | code.offset = entry->target - |
58 | (entry->code + JUMP_LABEL_NOP_SIZE); | 72 | (entry->code + JUMP_LABEL_NOP_SIZE); |
59 | BUG_ON(memcmp((void *)entry->code, &code, 5) != 0); | 73 | if (unlikely(memcmp((void *)entry->code, &code, 5) != 0)) |
74 | bug_at((void *)entry->code, __LINE__); | ||
60 | } | 75 | } |
61 | memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE); | 76 | memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE); |
62 | } | 77 | } |