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Subject[PATCH] x86-64: honor notify_die() returning NOTIFY_STOP
This requires making die() return a value, making its callers honor
this (and be prepared that it may return), and making oops_end() have
two additional parameters.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

arch/x86/kernel/cpu/mcheck/mce_64.c | 8 ++++----
arch/x86/kernel/traps_64.c | 23 +++++++++++++++--------
arch/x86/mm/fault_64.c | 12 ++++++------
include/asm-x86/kdebug.h | 4 ++--
4 files changed, 27 insertions(+), 20 deletions(-)

--- linux-2.6.24-rc5/arch/x86/kernel/cpu/mcheck/mce_64.c 2007-12-12 16:48:17.000000000 +0100
+++ 2.6.24-rc5-x86_64-notify-die-return/arch/x86/kernel/cpu/mcheck/mce_64.c 2007-12-04 16:20:14.000000000 +0100
@@ -192,10 +192,10 @@ void do_machine_check(struct pt_regs * r

atomic_inc(&mce_entry);

- if (regs)
- notify_die(DIE_NMI, "machine check", regs, error_code, 18,
- SIGKILL);
- if (!banks)
+ if ((regs
+ && notify_die(DIE_NMI, "machine check", regs, error_code,
+ 18, SIGKILL) == NOTIFY_STOP)
+ || !banks)
goto out2;

memset(&m, 0, sizeof(struct mce));
--- linux-2.6.24-rc5/arch/x86/kernel/traps_64.c 2007-12-12 16:48:17.000000000 +0100
+++ 2.6.24-rc5-x86_64-notify-die-return/arch/x86/kernel/traps_64.c 2007-12-04 17:50:33.000000000 +0100
@@ -496,7 +496,7 @@ unsigned __kprobes long oops_begin(void)
return flags;
}

-void __kprobes oops_end(unsigned long flags)
+void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
{
die_owner = -1;
bust_spinlocks(0);
@@ -505,12 +505,17 @@ void __kprobes oops_end(unsigned long fl
/* Nest count reaches zero, release the lock. */
__raw_spin_unlock(&die_lock);
raw_local_irq_restore(flags);
+ if (!regs) {
+ oops_exit();
+ return;
+ }
if (panic_on_oops)
panic("Fatal exception");
oops_exit();
+ do_exit(signr);
}

-void __kprobes __die(const char * str, struct pt_regs * regs, long err)
+int __kprobes __die(const char * str, struct pt_regs * regs, long err)
{
static int die_counter;
printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff,++die_counter);
@@ -524,7 +529,8 @@ void __kprobes __die(const char * str, s
printk("DEBUG_PAGEALLOC");
#endif
printk("\n");
- notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);
+ if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
+ return 1;
show_registers(regs);
add_taint(TAINT_DIE);
/* Executive summary in case the oops scrolled away */
@@ -533,6 +539,7 @@ void __kprobes __die(const char * str, s
printk(" RSP <%016lx>\n", regs->rsp);
if (kexec_should_crash(current))
crash_kexec(regs);
+ return 0;
}

void die(const char * str, struct pt_regs * regs, long err)
@@ -542,9 +549,9 @@ void die(const char * str, struct pt_reg
if (!user_mode(regs))
report_bug(regs->rip, regs);

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

void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
@@ -561,10 +568,10 @@ void __kprobes die_nmi(char *str, struct
crash_kexec(regs);
if (do_panic || panic_on_oops)
panic("Non maskable interrupt");
- oops_end(flags);
+ oops_end(flags, NULL, SIGBUS);
nmi_exit();
local_irq_enable();
- do_exit(SIGSEGV);
+ do_exit(SIGBUS);
}

static void __kprobes do_trap(int trapnr, int signr, char *str,
--- linux-2.6.24-rc5/arch/x86/mm/fault_64.c 2007-12-12 16:48:17.000000000 +0100
+++ 2.6.24-rc5-x86_64-notify-die-return/arch/x86/mm/fault_64.c 2007-12-04 16:18:59.000000000 +0100
@@ -228,9 +228,9 @@ static noinline void pgtable_bad(unsigne
tsk->thread.cr2 = address;
tsk->thread.trap_no = 14;
tsk->thread.error_code = error_code;
- __die("Bad pagetable", regs, error_code);
- oops_end(flags);
- do_exit(SIGKILL);
+ if (__die("Bad pagetable", regs, error_code))
+ regs = NULL;
+ oops_end(flags, regs, SIGKILL);
}

/*
@@ -542,11 +542,11 @@ no_context:
tsk->thread.cr2 = address;
tsk->thread.trap_no = 14;
tsk->thread.error_code = error_code;
- __die("Oops", regs, error_code);
+ if (__die("Oops", regs, error_code))
+ regs = NULL;
/* Executive summary in case the body of the oops scrolled away */
printk(KERN_EMERG "CR2: %016lx\n", address);
- oops_end(flags);
- do_exit(SIGKILL);
+ oops_end(flags, regs, SIGKILL);

/*
* We ran out of memory, or some other thing happened to us that made
--- linux-2.6.24-rc5/include/asm-x86/kdebug.h 2007-12-12 16:48:42.000000000 +0100
+++ 2.6.24-rc5-x86_64-notify-die-return/include/asm-x86/kdebug.h 2007-12-04 16:18:59.000000000 +0100
@@ -24,10 +24,10 @@ enum die_val {

extern void printk_address(unsigned long address);
extern void die(const char *,struct pt_regs *,long);
-extern void __die(const char *,struct pt_regs *,long);
+extern int __must_check __die(const char *, struct pt_regs *, long);
extern void show_registers(struct pt_regs *regs);
extern void dump_pagetable(unsigned long);
extern unsigned long oops_begin(void);
-extern void oops_end(unsigned long);
+extern void oops_end(unsigned long, struct pt_regs *, int signr);

#endif



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