Re: 5.15.0-rc1 armv7hl Workqueue: btrfs-delalloc btrfs_work_helper PC is at mmiocpy LR is at ZSTD_compressStream
From: Su Yue <hidden>
Date: 2021-10-04 12:04:20
On Tue 21 Sep 2021 at 21:56, David Sterba [off-list ref] wrote:
On Mon, Sep 20, 2021 at 06:13:07PM -0600, Chris Murphy wrote:quoted
00:09:50,679 EMERG kernel:[<c08bd768>] (mmiocpy) from [<c089c314>] (ZSTD_compressStream+0x184/0x294)The last function to fail is inside ZSTD implementation in kernel. If btrfs passes wrong data to zstd we'd see that also on non-arm builds, so guessing by mmiocpy as a copy-something function it could be some sort of alignment problem that works on x86_64 but throws an exception on arm as it's stricter about alignment.
It's about 32bits platforms. There is another report about x86 cpu. And it's reproduciable by running btrfs/004 (lzo and zstd)in x86 VM. In my arm64, all things are fine. And the bisection result is the highmem related patchset '[PATCH 0/6] Remove highmem allocations, kmap/kunmap'. Link: https://bugzilla.kernel.org/show_bug.cgi?id=214565 -- Su