Re: [PATCH v2 19/25] netfs: Speed up buffered reading

[Eduard Zingerman <eddyz87@gmail.com>]

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On Mon, 2024-09-23 at 23:33 +0100, David Howells wrote:
> Eduard Zingerman <eddyz87@gmail.com> wrote:
> 
> > - null-ptr-deref is triggered by access to page->pcp_list.next
> >   when list_del() is called from page_alloc.c:__rmqueue_pcplist(),
> 
> Can you tell me what the upstream commit ID of your kernel is?  (before any
> patches are stacked on it)

I used bpf-next tree, but could be reproduced with [1] as well,
commit ID [2]. Decoded dmesg for this commit ID in [3].

[1] git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[2] abf2050f51fd ("Merge tag 'media/v6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media")
[3] https://gist.github.com/eddyz87/af39e04069c6ca30e66c3032c0384b8e

> If you can modify your kernel, can you find the following in fs/netfs/:
> 
> buffered_read.c:127:			new = kmalloc(sizeof(*new), GFP_NOFS);
> buffered_read.c:353:	folioq = kmalloc(sizeof(*folioq), GFP_KERNEL);
> buffered_read.c:458:	folioq = kmalloc(sizeof(*folioq), GFP_KERNEL);
> misc.c:25:		tail = kmalloc(sizeof(*tail), GFP_NOFS);
> 
> and change the kmalloc to kzalloc?

No changes in behaviour.


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