Messages in this thread Patch in this message | | | Date | Tue, 29 Jan 2002 16:13:31 -0800 (PST) | From | James Simmons <> | Subject | Re: [Linux-fbdev-devel] Re: [PATCH?] Crash in 2.4.17/ptrace |
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> Ah, thanks. Also I missed sbusfb.c (not that it was fatal - the driver > got it right anyway).
Great.
> Here's the current patch. After some discussion with Ben > Herrenschmidt, it now sets VM_IO against the vma *before* > calling the subdriver's mmap method, just in case the > driver really does want to clear that flag (presumably, a shadow > buffer in main memory).
I also thought about it as well. Never thought about the issue with shadow buffers. Is it safe to move it before if (fb->fb_mmap)?
> --- linux-2.4.18-pre7/drivers/video/fbmem.c Fri Dec 21 11:19:14 2001 > +++ linux-akpm/drivers/video/fbmem.c Tue Jan 29 14:57:00 2002 > @@ -541,6 +541,16 @@ fb_mmap(struct file *file, struct vm_are > if (fb->fb_mmap) { > int res; > lock_kernel(); > + /* > + * This is an IO map - tell maydump to skip this VMA. > + * If, for some reason, the sub-driver wishes to allow the > + * mapping to be dumpable and accessible via ptrace then > + * it may clear VM_IO later. > + * (This only makes sense if the buffer is actually > + * in main memory, and is described by a page struct in > + * mem_map[]) > + */ > + vma->vm_flags |= VM_IO; > res = fb->fb_mmap(info, file, vma); > unlock_kernel(); > return res;
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