Messages in this thread | | | Date | Wed, 9 Sep 2015 04:51:27 +0200 | Subject | Re: [llvmlinux] percpu | bitmap issue? (Cannot boot on bare metal due to a kernel NULL pointer dereference) | From | Sedat Dilek <> |
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On Wed, Sep 9, 2015 at 4:29 AM, Baoquan He <bhe@redhat.com> wrote: > > Seems it happened when call num_possible_cpus() which is a inline > function to call __bitmap_weight(). So did you check > lib/bitmap.c:__bitmap_weight() by objdump? > > setup_percpu: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:1 nr_node_ids:1 >
[ CC->TO Denys ]
Hi Boaquan,
Thanks for your reply.
I tried a lot in the meantime :-).
For example I applied a patch from Denys Vlasenko <dvlasenk@redhat.com>...
commit 1a1d48a4a8fde49aedc045d894efe67173d59fe0 "linux/bitmap: Force inlining of bitmap weight functions"
...on top of Linux v4.2.
This resulted in the same call-trace in QEMU.
I hacked around to only re-build mm/percpu.c with GCC (rest with CLANG) with some guidance from Linus (compiler warapper-script) etc.
What do you need for outputs? objdump of lib/bitmap.o? From both builds - with GCC and CLANG?
Please give me clear instructions, Thanks!
Regards, - Sedat -
[1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1a1d48a4a8fde49aedc045d894efe67173d59fe0
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