Re: [Fastboot] [2/2] kdump: Save trap information for lateranalyzis

From: Alexander Nyberg
Date: Wed May 18 2005 - 10:01:18 EST


If we are faulting in kernel it is quite possible this will lead to a
panic. Save trap number, cr2 (in case of page fault) and error_code in
the current thread (these fields already exist for signal delivery but
are not used here).

This helps later kdump crash analyzing from user-space (a script has
been submitted to dig this info out in gdb).


Signed-off-by: Alexander Nyberg <alexn@xxxxxxxxx>

Index: mm/arch/i386/mm/fault.c
===================================================================
--- mm.orig/arch/i386/mm/fault.c 2005-05-18 16:39:04.000000000 +0200
+++ mm/arch/i386/mm/fault.c 2005-05-18 16:39:20.000000000 +0200
@@ -469,6 +469,9 @@
printk(KERN_ALERT "*pte = %08lx\n", page);
}
#endif
+ tsk->thread.cr2 = address;
+ tsk->thread.trap_no = 14;
+ tsk->thread.error_code = error_code;
die("Oops", regs, error_code);
bust_spinlocks(0);
do_exit(SIGKILL);
Index: mm/arch/i386/kernel/traps.c
===================================================================
--- mm.orig/arch/i386/kernel/traps.c 2005-05-18 16:39:04.000000000 +0200
+++ mm/arch/i386/kernel/traps.c 2005-05-18 16:39:20.000000000 +0200
@@ -410,6 +410,10 @@
static void do_trap(int trapnr, int signr, char *str, int vm86,
struct pt_regs * regs, long error_code, siginfo_t *info)
{
+ struct task_struct *tsk = current;
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = trapnr;
+
if (regs->eflags & VM_MASK) {
if (vm86)
goto vm86_trap;
@@ -420,9 +424,6 @@
goto kernel_trap;

trap_signal: {
- struct task_struct *tsk = current;
- tsk->thread.error_code = error_code;
- tsk->thread.trap_no = trapnr;
if (info)
force_sig_info(signr, info, tsk);
else
@@ -537,6 +538,9 @@
}
put_cpu();

+ current->thread.error_code = error_code;
+ current->thread.trap_no = 13;
+
if (regs->eflags & VM_MASK)
goto gp_in_vm86;

@@ -977,9 +981,9 @@
error_code);
return;
}
- die_if_kernel("cache flush denied", regs, error_code);
current->thread.trap_no = 19;
current->thread.error_code = error_code;
+ die_if_kernel("cache flush denied", regs, error_code);
force_sig(SIGSEGV, current);
}
}


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/