The stack trace starts getting printed even before the kernel boots -
the first occurrence is below. It then repeats printing so frequently
that the system is unusable (and I could not run the Xenomai task).
I've attached the highmem_32.c I used.
Tomas
...
[ 14.232387] I-pipe 2.0-03: pipeline enabled.
[ 14.233719] Console: colour VGA+ 80x25
[ 14.233723] console [tty0] enabled
[ 14.235351] console [ttyS0] enabled
[ 14.477149] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[ 14.484474] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[ 14.725139] Memory: 3588720k/4194304k available (2152k kernel code, 78516k
reserved, 904k data, 296k init, 2751016k highme
m)
[ 14.736370] virtual kernel memory layout:
[ 14.736371] fixmap : 0xfff52000 - 0xfffff000 ( 692 kB)
[ 14.736371] pkmap : 0xff800000 - 0xffc00000 (4096 kB)
[ 14.736372] vmalloc : 0xf8800000 - 0xff7fe000 ( 111 MB)
[ 14.736373] lowmem : 0xc0000000 - 0xf8000000 ( 896 MB)
[ 14.736374] .init : 0xc0404000 - 0xc044e000 ( 296 kB)
[ 14.736375] .data : 0xc031a3a6 - 0xc03fc664 ( 904 kB)
[ 14.736375] .text : 0xc0100000 - 0xc031a3a6 (2152 kB)
[ 14.780692] Checking if this processor honours the WP bit even in supervisor
mode... Ok.
[ 14.848936] Calibrating delay using timer specific routine.. 7583.33
BogoMIPS (lpj=3791666)
[ 14.857374] Security Framework initialized
[ 14.861493] SELinux: Disabled at boot.
[ 14.865360] Mount-cache hash table entries: 512
[ 14.869987] Wrong address passed to kunmap_atomic!
[ 14.874796] c03ffebc 00000000 00000000 00000003 00000000 c0105fbd c0394b4a 00048000
[ 14.883277] 00000003 c011aa9e c039a858 c16f8240 c16f8220 f7c12000 c019e9bd 0000007a
[ 14.891970] 00000044 00000000 c01b7210 f7c11000 00000001 00000001 00000000 c03dbc80
[ 14.900661] Call Trace:
[ 14.903348] [<c0105fbd>] show_stack+0x2d/0x40
[ 14.907856] [<c011aa9e>] kunmap_atomic+0x4e/0xf0
[ 14.912617] [<c019e9bd>] get_page_from_freelist+0x2ed/0x4d0
[ 14.918333] [<c01b7210>] do_ccupdate_local+0x0/0x40
[ 14.923358] [<c019ec47>] __alloc_pages+0x57/0x360
[ 14.928208] [<c01b7e89>] enable_cpucache+0x29/0xb0
[ 14.933141] [<c01d15c5>] alloc_vfsmnt+0x95/0xd0
[ 14.937816] [<c019efec>] get_zeroed_page+0x3c/0x50
[ 14.942750] [<c01bc8f6>] vfs_kern_mount+0x56/0x120
[ 14.947682] [<c01bc9d2>] kern_mount_data+0x12/0x20
[ 14.952616] [<c041842d>] proc_root_init+0x2d/0xb0
[ 14.957464] [<c0404a6d>] start_kernel+0x2fd/0x3a0
[ 14.962311] [<c0404140>] unknown_bootoption+0x0/0x1f0
[ 14.967506] =======================
[ 14.971152] monitor/mwait feature present.
[ 14.975271] CPU: Trace cache: 12K uops, L1 D cache: 16K
[ 14.980553] CPU: L2 cache: 2048K
[ 14.983804] CPU: Physical Processor ID: 0
...
Gilles Chanteperdrix wrote:
Ok. In the mean time, I think I may have found the reason for the
crash. Try this patch, you should get a printk and a stack trace
instead of the bug.
#include <linux/highmem.h>
#include <linux/module.h>
static struct {
const char *file;
unsigned line;
} last_km_user0 [NR_CPUS];
void *kmap(struct page *page)
{
might_sleep();
if (!PageHighMem(page))
return page_address(page);
return kmap_high(page);
}
void kunmap(struct page *page)
{
if (in_interrupt())
BUG();
if (!PageHighMem(page))
return;
kunmap_high(page);
}
/*
* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
* no global lock is needed and because the kmap code must perform a global TLB
* invalidation when the kmap pool wraps.
*
* However when holding an atomic kmap is is not legal to sleep, so atomic
* kmaps are appropriate for short, tight code paths only.
*/
void *_kmap_atomic_prot(struct page *page, enum km_type type,
pgprot_t prot, const char *file, unsigned line)
{
enum fixed_addresses idx;
unsigned long vaddr;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
if (!pte_none(*(kmap_pte-idx))) {
if (type == KM_USER0)
printk("KM_USER0 already mapped at %s:%d\n",
last_km_user0[smp_processor_id()].file,
last_km_user0[smp_processor_id()].line);
BUG();
} else if (type == KM_USER0) {
last_km_user0[smp_processor_id()].file = file;
last_km_user0[smp_processor_id()].line = line;
}
set_pte(kmap_pte-idx, mk_pte(page, prot));
arch_flush_lazy_mmu_mode();
return (void *)vaddr;
}
void *_kmap_atomic(struct page *page, enum km_type type,
const char *file, unsigned line)
{
return _kmap_atomic_prot(page, type, kmap_prot, file, line);
}
void kunmap_atomic(void *kvaddr, enum km_type type)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
/*
* Force other mappings to Oops if they'll try to access this pte
* without first remap it. Keeping stale mappings around is a bad idea
* also, in case the page changes cacheability attributes or becomes
* a protected page in a hypervisor.
*/
if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
kpte_clear_flush(kmap_pte-idx, vaddr);
else {
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(vaddr < PAGE_OFFSET);
BUG_ON(vaddr >= (unsigned long)high_memory);
#endif
printk("Wrong address passed to kunmap_atomic!\n");
show_stack(NULL, NULL);
kpte_clear_flush(kmap_pte-idx, __fix_to_virt(FIX_KMAP_BEGIN+idx));
}
if (type == KM_USER0) {
last_km_user0[smp_processor_id()].file = NULL;
last_km_user0[smp_processor_id()].line = 0;
}
arch_flush_lazy_mmu_mode();
pagefault_enable();
}
/* This is the same as kmap_atomic() but can map memory that doesn't
* have a struct page associated with it.
*/
void *_kmap_atomic_pfn(unsigned long pfn, enum km_type type,
const char *file, unsigned line)
{
enum fixed_addresses idx;
unsigned long vaddr;
pagefault_disable();
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
if (!pte_none(*(kmap_pte-idx))) {
if (type == KM_USER0)
printk("KM_USER0 already mapped at %s:%d\n",
last_km_user0[smp_processor_id()].file,
last_km_user0[smp_processor_id()].line);
BUG();
} else if (type == KM_USER0) {
last_km_user0[smp_processor_id()].file = file;
last_km_user0[smp_processor_id()].line = line;
}
set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
arch_flush_lazy_mmu_mode();
return (void*) vaddr;
}
struct page *kmap_atomic_to_page(void *ptr)
{
unsigned long idx, vaddr = (unsigned long)ptr;
pte_t *pte;
if (vaddr < FIXADDR_START)
return virt_to_page(ptr);
idx = virt_to_fix(vaddr);
pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
return pte_page(*pte);
}
EXPORT_SYMBOL(kmap);
EXPORT_SYMBOL(kunmap);
EXPORT_SYMBOL(_kmap_atomic);
EXPORT_SYMBOL(kunmap_atomic);
EXPORT_SYMBOL(kmap_atomic_to_page);
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