Re: 2.5.69+bk: oops in apmd after waking up from suspend mode

From: Alex Riesen (alexander.riesen@synopsys.COM)
Date: Tue May 20 2003 - 05:48:20 EST

Carl-Daniel Hailfinger, Tue, May 20, 2003 12:39:54 +0200:
> >>>>EIP is at fix_processor_context+0x5f/0x100
> >>>>Process kapmd (pid: 4, threadinfo=c5f0e000 task=c5fbc640)
> >>>
> >>>After receiving Alex' .config and gcc version (3.2.3), I've been
> >>>able to decipher this. current->mm is NULL in the kapmd task. The call
> >>>
> >>> load_LDT(&current->mm->context); /* This does lldt */
> >>>
> >>>in fix_processor_context() computes the address of context as
> >>>(current->mm)+0x7c, which is 0x7c. load_LDT_nolock() dereferences
> >>>0x7c+0x14 (void *segments = pc->ldt) and the oops follows.
> >>>
> >>>As to _why_ kapmd's current->mm is NULL, I don't know. It isn't
> >>>when I test APM suspend in 2.5.69-bk. A lot of code dereferences
> >>>current->mm without checking, so I guess current->mm==NULL is a bug.
> >>
> >>i just go and try it with the latest -bk.
> >
> > no change. Still oopses.
>
> Could you try to compile with gcc-3.3? In another thread (2.5.69-mm6:
> pccard oops) this helped IIRC. I'm suspecting gcc 3.2.3 generates
> incorrect code for some cases.

I preferably not. Zwane already mentioned that current->mm allowed to
be NULL for kernel threads, and i seen it be NULL even before suspending.

-alex

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