diff options
| -rw-r--r-- | arch/x86/kernel/static_call.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c index b70670a98597..77a9316da435 100644 --- a/arch/x86/kernel/static_call.c +++ b/arch/x86/kernel/static_call.c @@ -186,6 +186,19 @@ EXPORT_SYMBOL_GPL(arch_static_call_transform); */ bool __static_call_fixup(void *tramp, u8 op, void *dest) { + unsigned long addr = (unsigned long)tramp; + /* + * Not all .return_sites are a static_call trampoline (most are not). + * Check if the 3 bytes after the return are still kernel text, if not, + * then this definitely is not a trampoline and we need not worry + * further. + * + * This avoids the memcmp() below tripping over pagefaults etc.. + */ + if (((addr >> PAGE_SHIFT) != ((addr + 7) >> PAGE_SHIFT)) && + !kernel_text_address(addr + 7)) + return false; + if (memcmp(tramp+5, tramp_ud, 3)) { /* Not a trampoline site, not our problem. */ return false; |