While loading X, I get this oops. The weird thing is that I don't use
framebuffer. I compiled with gcc 3.2.2 but the code generated looks weird.
Virgin gcc 3.2.2 on a pentium III.
Oops, followed by my unskilled ruminations:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
printing eip:
c0275a13
*pde = 00000000
Oops: 0000 [#1]
CPU: 0
EIP: 0060:[fb_open+51/208] Not tainted
EFLAGS: 00013282
EIP is at fb_open+0x33/0xd0
eax: 00000000 ebx: 000000e0 ecx: 00000001 edx: 00000001
esi: cbd436e0 edi: 00000000 ebp: 00000000 esp: c9589f24
ds: 007b es: 007b ss: 0068
Process XFree86 (pid: 497, threadinfo=c9588000 task=c96b27e0)
Stack: c9554720 cbfea4e0 00000000 c9554720 c89b0604 c0150bde c89b0604 c9554720
c9554720 c89b0604 cbfea4e0 c01481ca c89b0604 c9554720 00000002 bffffb78
cbfe2000 c9588000 c0148008 c937e940 cbfea4e0 00000002 c9589f80 c937e940
Call Trace:
[chrdev_open+94/112] chrdev_open+0x5e/0x70
[dentry_open+442/480] dentry_open+0x1ba/0x1e0
[filp_open+104/112] filp_open+0x68/0x70
[sys_open+91/144] sys_open+0x5b/0x90
[syscall_call+7/11] syscall_call+0x7/0xb
Code: 8b 00 85 c0 74 0b 83 38 02 74 6a ff 80 c0 00 00 00 85 d2 b8
gdb traces fb_open+0x33 to:
(gdb) l *(fb_open+0x33)
0xe23 is in fb_open (include/linux/module.h:286).
281 #define local_inc(x) atomic_inc(x)
282 #define local_dec(x) atomic_dec(x)
283 #endif
284
285 static inline int try_module_get(struct module *module)
286 {
287 int ret = 1;
288
289 if (module) {
290 unsigned int cpu = get_cpu();
>From the oops: Code: 8b 00 85 c0 74 0b 83 38 02 74 6a ff 80 c0 00 00 00 85
d2 b8
This output looks somewhat bogus to me as it appears to try to dereference
'module' before it has been tested for zero or not:
static inline int try_module_get(struct module *module)
{
c0275a08: 8b 86 94 01 00 00 mov 0x194(%esi),%eax
int ret = 1;
c0275a0e: ba 01 00 00 00 mov $0x1,%edx
c0275a13: 8b 00 mov (%eax),%eax
if (module) {
c0275a15: 85 c0 test %eax,%eax
c0275a17: 74 0b je c0275a24 <fb_open+0x44>
c0275a19: 83 38 02 cmpl $0x2,(%eax)
c0275a1c: 74 6a je c0275a88 <fb_open+0xa8>
which is called from fb_open:
static int
fb_open(struct inode *inode, struct file *file)
{
int fbidx = minor(inode->i_rdev);
struct fb_info *info;
int res = 0;
#ifdef CONFIG_KMOD
if (!(info = registered_fb[fbidx]))
try_to_load(fbidx);
#endif /* CONFIG_KMOD */
if (!(info = registered_fb[fbidx]))
return -ENODEV;
if (!try_module_get(info->fbops->owner))
return -ENODEV;
if (info->fbops->fb_open) {
res = info->fbops->fb_open(info,1);
if (res)
module_put(info->fbops->owner);
}
return res;
}
This suddenly appeared in 2.5.66, 2.5.65 works flawlessly with the same
compiler.
Regards,
bert
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This archive was generated by hypermail 2b29 : Mon Mar 31 2003 - 22:00:19 EST