On Fri, Oct 14, 2022 at 01:58:18PM -0700, Guenter Roeck wrote: > Hi, > > On Wed, Aug 17, 2022 at 07:18:19PM +0900, Hyeonggon Yoo wrote: > > There is not much benefit for serving large objects in kmalloc(). > > Let's pass large requests to page allocator like SLUB for better > > maintenance of common code. > > > > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx> > > Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> > > --- > > This patch results in a WARNING backtrace in all mips and sparc64 > emulations. > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 0 at mm/slab_common.c:729 kmalloc_slab+0xc0/0xdc > Modules linked in: > CPU: 0 PID: 0 Comm: swapper Not tainted 6.0.0-11990-g9c9155a3509a #1 > Stack : ffffffff 801b2a18 80dd0000 00000004 00000000 00000000 81023cd4 00000000 > 81040000 811a9930 81040000 8104a628 81101833 00000001 81023c78 00000000 > 00000000 00000000 80f5d858 81023b98 00000001 00000023 00000000 ffffffff > 00000000 00000064 00000002 81040000 81040000 00000001 80f5d858 000002d9 > 00000000 00000000 80000000 80002000 00000000 00000000 00000000 00000000 > ... > Call Trace: > [<8010a2bc>] show_stack+0x38/0x118 > [<80cf5f7c>] dump_stack_lvl+0xac/0x104 > [<80130d7c>] __warn+0xe0/0x224 > [<80cdba5c>] warn_slowpath_fmt+0x64/0xb8 > [<8028c058>] kmalloc_slab+0xc0/0xdc > > irq event stamp: 0 > hardirqs last enabled at (0): [<00000000>] 0x0 > hardirqs last disabled at (0): [<00000000>] 0x0 > softirqs last enabled at (0): [<00000000>] 0x0 > softirqs last disabled at (0): [<00000000>] 0x0 > ---[ end trace 0000000000000000 ]--- > > Guenter Hi. Thank you so much for this report! Hmm so SLAB tries to find kmalloc cache for freelist index array using kmalloc_slab() directly, and it becomes problematic when size of the array is larger than PAGE_SIZE * 2. Will send a fix soon. -- Thanks, Hyeonggon
