Re: [PATCH 1/3] uprobes: install_breakpoint() should fail ifis_swbp_insn() == T
From: Oleg Nesterov
Date: Sat Jun 02 2012 - 14:24:41 EST
On 06/01, Oleg Nesterov wrote:
>
> while (more--) {
> info = kmalloc(sizeof(struct map_info), GFP_KERNEL);
> if (!info) {
> curr = ERR_PTR(-ENOMEM);
> goto out;
> }
> info->next = prev;
> prev = info;
> }
This should be "do ... while (--more)", otherwise it seems to work
and really helps.
I did the simple test under qemu. Currently uprobe_register() hangs
"forever" if the probed addr has 10000 mappings, I'have stopped qemu
after several minutes.
With the new code uprobe_register() needs 0.403s to complete.
We can also change build_map_info() to try GFP_NOWAIT | GFP_NOMEMALLOC
under i_mmap_mutex first, not sure this is really needed.
I'll write the changelog and send the patch...
Do you see any problems with this approach?
Oleg.
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