[PATCH 2/7] x86, dumpstack: let signr=0 signal no do_exit

Alexander van Heukelum
2008-10-22T10:09:55Z

Change oops_end such that signr=0 signals that do_exit
is not to be called.

Currently, each use of __die is soon followed by a call
to oops_end and 'regs' is set to NULL if oops_end is expected
not to call do_exit. Change all such pairs to set signr=0
instead. On x86_64 oops_end is used 'bare' in die_nmi; use
signr=0 instead of regs=NULL there, too.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
arch/x86/kernel/dumpstack_32.c | 7 ++++---
arch/x86/kernel/dumpstack_64.c | 9 +++++----
arch/x86/mm/fault.c | 11 +++++++----
3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 5493d31..7c22f99 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -318,7 +318,7 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
__raw_spin_unlock(&die_lock);
raw_local_irq_restore(flags);

- if (!regs)
+ if (!signr)
return;

if (in_interrupt())
@@ -371,17 +371,18 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err)
void die(const char *str, struct pt_regs *regs, long err)
{
unsigned long flags = oops_begin();
+ int sig = SIGSEGV;

if (die_nest_count < 3) {
report_bug(regs->ip, regs);

if (__die(str, regs, err))
- regs = NULL;
+ sig = 0;
} else {
printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
}

- oops_end(flags, regs, SIGSEGV);
+ oops_end(flags, regs, sig);
}

static DEFINE_SPINLOCK(nmi_print_lock);
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 96a5db7..ffefea6 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -465,7 +465,7 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
/* Nest count reaches zero, release the lock. */
__raw_spin_unlock(&die_lock);
raw_local_irq_restore(flags);
- if (!regs) {
+ if (!signr) {
oops_exit();
return;
}
@@ -509,13 +509,14 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err)
void die(const char *str, struct pt_regs *regs, long err)
{
unsigned long flags = oops_begin();
+ int sig = SIGSEGV;

if (!user_mode(regs))
report_bug(regs->ip, regs);

if (__die(str, regs, err))
- regs = NULL;
- oops_end(flags, regs, SIGSEGV);
+ sig = 0;
+ oops_end(flags, regs, sig);
}

notrace __kprobes void
@@ -539,7 +540,7 @@ die_nmi(char *str, struct pt_regs *regs, int do_panic)
crash_kexec(regs);
if (do_panic || panic_on_oops)
panic("Non maskable interrupt");
- oops_end(flags, NULL, SIGBUS);
+ oops_end(flags, regs, 0);
nmi_exit();
local_irq_enable();
do_exit(SIGBUS);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 8e52e68..ed9ee30 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -415,6 +415,7 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
unsigned long error_code)
{
unsigned long flags = oops_begin();
+ int sig = SIGKILL;
struct task_struct *tsk;

printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
@@ -425,8 +426,8 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
tsk->thread.trap_no = 14;
tsk->thread.error_code = error_code;
if (__die("Bad pagetable", regs, error_code))
- regs = NULL;
- oops_end(flags, regs, SIGKILL);
+ sig = 0;
+ oops_end(flags, regs, sig);
}
#endif

@@ -594,6 +595,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)

#ifdef CONFIG_X86_64
unsigned long flags;
+ int sig;
#endif

tsk = current;
@@ -868,11 +870,12 @@ no_context:
bust_spinlocks(0);
do_exit(SIGKILL);
#else
+ sig = SIGKILL;
if (__die("Oops", regs, error_code))
- regs = NULL;
+ sig = 0;
/* Executive summary in case the body of the oops scrolled away */
printk(KERN_EMERG "CR2: %016lx\n", address);
- oops_end(flags, regs, SIGKILL);
+ oops_end(flags, regs, sig);
#endif

/*
--
1.5.4.3