Hi Dave,
On Fri, 2010-02-26 at 09:50 -0500, Dave Anderson wrote:
> ----- "Michael Holzheu" <holzheu@xxxxxxxxxxxxxxxxxx> wrote:
>
> > Hi Dave,
> >
> > This patch fixes several bugs in the s390 stack backtrace code
> > * Add panic stack as second interrupt stack
> > * Fix printing of access registers (4 bytes instead of 8 bytes)
> > * Use u64 for s390x register 14
> > * Fix interrupt stack handling for s390x (use 160 byte overhead
> > instead of 96)
>
> The patch looks OK upon first glance -- can you verify that it's
> absolutely backwards-compatible to earlier kernel versions?
I tested vanilla 2.6.32, RHEL5, SLES10 and SLES11.
But I found a bug with RHEL4:
Older Linux kernels for s390 can be built so that the panic stack is
not set (CONFIG_CHECK_STACK kernel built option):
*(lowcore_ptr[i]) = S390_lowcore;
lowcore_ptr[i]->async_stack = stack + (ASYNC_SIZE);
#ifdef CONFIG_CHECK_STACK
stack = __get_free_pages(GFP_KERNEL,0);
if (stack == 0ULL)
panic("smp_boot_cpus failed to allocate memory\n");
lowcore_ptr[i]->panic_stack = stack + (PAGE_SIZE);
#endif
RHEL4 has not defined CONFIG_CHECK_STACK. Therefore the following
patch adds a check, so that the panic stack is only used, when
it is there.
---
s390.c | 2 ++
s390x.c | 2 ++
2 files changed, 4 insertions(+)
--- a/s390.c
+++ b/s390.c
@@ -581,6 +581,8 @@ static void s390_get_int_stack(char *sta
if (!MEMBER_EXISTS("_lowcore", stack_name))
return;
stack_addr = ULONG(lc + MEMBER_OFFSET("_lowcore", stack_name));
+ if (stack_addr == 0)
+ return;
readmem(stack_addr - INT_STACK_SIZE, KVADDR, int_stack,
INT_STACK_SIZE, stack_name, FAULT_ON_ERROR);
*start = stack_addr - INT_STACK_SIZE;
--- a/s390x.c
+++ b/s390x.c
@@ -813,6 +813,8 @@ static void s390x_get_int_stack(char *st
if (!MEMBER_EXISTS("_lowcore", stack_name))
return;
stack_addr = ULONG(lc + MEMBER_OFFSET("_lowcore", stack_name));
+ if (stack_addr == 0)
+ return;
readmem(stack_addr - INT_STACK_SIZE, KVADDR, int_stack,
INT_STACK_SIZE, stack_name, FAULT_ON_ERROR);
*start = stack_addr - INT_STACK_SIZE;
s390: Check for kernels that do not have defined panic stack
Older Linux kernels for s390 can be built so that the panic stack is
not set (CONFIG_CHECK_STACK kernel built option):
*(lowcore_ptr[i]) = S390_lowcore;
lowcore_ptr[i]->async_stack = stack + (ASYNC_SIZE);
#ifdef CONFIG_CHECK_STACK
stack = __get_free_pages(GFP_KERNEL,0);
if (stack == 0ULL)
panic("smp_boot_cpus failed to allocate memory\n");
lowcore_ptr[i]->panic_stack = stack + (PAGE_SIZE);
#endif
RHEL4 has not defined CONFIG_CHECK_STACK. Therefore this patch adds a check,
so that the panic stack is only used, when it is there.
---
s390.c | 2 ++
s390x.c | 2 ++
2 files changed, 4 insertions(+)
--- a/s390.c
+++ b/s390.c
@@ -581,6 +581,8 @@ static void s390_get_int_stack(char *sta
if (!MEMBER_EXISTS("_lowcore", stack_name))
return;
stack_addr = ULONG(lc + MEMBER_OFFSET("_lowcore", stack_name));
+ if (stack_addr == 0)
+ return;
readmem(stack_addr - INT_STACK_SIZE, KVADDR, int_stack,
INT_STACK_SIZE, stack_name, FAULT_ON_ERROR);
*start = stack_addr - INT_STACK_SIZE;
--- a/s390x.c
+++ b/s390x.c
@@ -813,6 +813,8 @@ static void s390x_get_int_stack(char *st
if (!MEMBER_EXISTS("_lowcore", stack_name))
return;
stack_addr = ULONG(lc + MEMBER_OFFSET("_lowcore", stack_name));
+ if (stack_addr == 0)
+ return;
readmem(stack_addr - INT_STACK_SIZE, KVADDR, int_stack,
INT_STACK_SIZE, stack_name, FAULT_ON_ERROR);
*start = stack_addr - INT_STACK_SIZE;
--
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