Re: [PATCH] md/raid0: use kvzalloc/kvfree for strip_zone and devlist allocations

[Gregory Price <gourry@gourry.net>]

On Tue, Apr 07, 2026 at 01:06:19PM +0800, Yu Kuai wrote:
> Hi,
> 
> 在 2026/3/9 7:42, Gregory Price 写道:
> > syzbot reported a WARNING at mm/page_alloc.c:__alloc_frozen_pages_noprof()
> > triggered by create_strip_zones() in the RAID0 driver.
> >
> > When raid_disks is large, the allocation size exceeds MAX_PAGE_ORDER (4MB
> > on x86), causing WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER).
> >
> > Convert the strip_zone and devlist allocations from kzalloc/kzalloc_objs to
> > kvzalloc/kvzalloc_objs, which first attempts a contiguous allocation with
> > __GFP_NOWARN and then falls back to vmalloc for large sizes. Convert the
> > corresponding kfree calls to kvfree.
> >
> > Both arrays are pure metadata lookup tables (arrays of pointers and zone
> > descriptors) accessed only via indexing, so they do not require physically
> > contiguous memory.
> >
> > Reported-by:syzbot+924649752adf0d3ac9dd@syzkaller.appspotmail.com
> 
> Reported-by should be followed by Closes tag, applied tom md-7.1 with following tag:
> Closes:[syzbot] [mm?] WARNING in create_strip_zones - syzbot <https://lore.kernel.org/all/69adaba8.a00a0220.b130.0005.GAE@google.com/>
>

Ah, gotcha, didn't realize there was automation here, first time i've
poked at a syzbot report.

Thanks!

> > Signed-off-by: Gregory Price<gourry@gourry.net>
> > ---
> >   drivers/md/raid0.c | 18 +++++++++---------
> >   1 file changed, 9 insertions(+), 9 deletions(-)
> 
> -- 
> Thansk,
> Kuai