From: David Wilder <dwilder@xxxxxxxxxx> Running a probe on s390 with a probe address that is not 4 byte aligned results in a Kernel BUG. The problem is that the stura instruction used by swap_instruction requires the destination address to be 4 byte aligned. As stura only writes 4 bytes, aligning to the next 4 byte aligned address results in the breakpoint instruction being stored past the probe address. The fix is to align the address backward (to the previous 4 byte aligned address) and writing the two byte breakpoint instruction in the appropriate bytes. Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Signed-off-by: David Wilder <dwilder@xxxxxxxxxx> Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> --- arch/s390/kernel/kprobes.c | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6/arch/s390/kernel/kprobes.c =================================================================== --- linux-2.6.orig/arch/s390/kernel/kprobes.c +++ linux-2.6/arch/s390/kernel/kprobes.c @@ -167,7 +167,7 @@ static int __kprobes swap_instruction(vo * shall not cross any page boundaries (vmalloc area!) when writing * the new instruction. */ - addr = (u32 *)ALIGN((unsigned long)args->ptr, 4); + addr = (u32 *)((unsigned long)args->ptr & -4UL); if ((unsigned long)args->ptr & 2) instr = ((*addr) & 0xffff0000) | args->new; else -- - To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
