diff options
| author | Chuck Ebbert <cebbert@redhat.com> | 2007-08-10 22:31:11 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-11 15:58:14 -0700 |
| commit | 3dab307e527f2a9bbb4f9d00240374bb93d1945f (patch) | |
| tree | 3e9a83d6cc1cee1dcfedff700c0b4aeebaa2f8d5 /arch/i386/kernel/doublefault.c | |
| parent | 5fe4486c79cdc8dbbb2a9c3f884a5ad0830a5a23 (diff) | |
| download | lwn-3dab307e527f2a9bbb4f9d00240374bb93d1945f.tar.gz lwn-3dab307e527f2a9bbb4f9d00240374bb93d1945f.zip | |
i386: Fix double fault handler
The new percpu code has apparently broken the doublefault handler
when CONFIG_DEBUG_SPINLOCK is set. Doublefault is handled by
a hardware task, making the check
SPIN_BUG_ON(lock->owner == current, lock, "recursion");
fault because it uses the FS register to access the percpu data
for current, and that register is zero in the new TSS. (The trace
I saw was on 2.6.20 where it was GS, but it looks like this will
still happen with FS on 2.6.22.)
Initializing FS in the doublefault_tss should fix it.
AK: Also fix broken ptr_ok() and turn printks into KERN_EMERG
AK: And add a PANIC prefix to make clear the system will hang
AK: (e.g. x86-64 will recover)
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386/kernel/doublefault.c')
| -rw-r--r-- | arch/i386/kernel/doublefault.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/arch/i386/kernel/doublefault.c b/arch/i386/kernel/doublefault.c index 265c5597efb0..40978af630e7 100644 --- a/arch/i386/kernel/doublefault.c +++ b/arch/i386/kernel/doublefault.c @@ -13,7 +13,7 @@ static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE]; #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE) -#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + 0x1000000) +#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + MAXMEM) static void doublefault_fn(void) { @@ -23,23 +23,23 @@ static void doublefault_fn(void) store_gdt(&gdt_desc); gdt = gdt_desc.address; - printk("double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size); + printk(KERN_EMERG "PANIC: double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size); if (ptr_ok(gdt)) { gdt += GDT_ENTRY_TSS << 3; tss = *(u16 *)(gdt+2); tss += *(u8 *)(gdt+4) << 16; tss += *(u8 *)(gdt+7) << 24; - printk("double fault, tss at %08lx\n", tss); + printk(KERN_EMERG "double fault, tss at %08lx\n", tss); if (ptr_ok(tss)) { struct i386_hw_tss *t = (struct i386_hw_tss *)tss; - printk("eip = %08lx, esp = %08lx\n", t->eip, t->esp); + printk(KERN_EMERG "eip = %08lx, esp = %08lx\n", t->eip, t->esp); - printk("eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n", + printk(KERN_EMERG "eax = %08lx, ebx = %08lx, ecx = %08lx, edx = %08lx\n", t->eax, t->ebx, t->ecx, t->edx); - printk("esi = %08lx, edi = %08lx\n", + printk(KERN_EMERG "esi = %08lx, edi = %08lx\n", t->esi, t->edi); } } @@ -63,6 +63,7 @@ struct tss_struct doublefault_tss __cacheline_aligned = { .cs = __KERNEL_CS, .ss = __KERNEL_DS, .ds = __USER_DS, + .fs = __KERNEL_PERCPU, .__cr3 = __pa(swapper_pg_dir) } |