Re: [Crash-utility] [PATCH] Fix the "kmem -s" option for Linux 5.7 and later kernels

On Sat, May 29, 2021 at 4:43 AM Kazuhito Hagio <kazuhito.hagio(a)gmail.com&gt; wrote: calculation formula in the freelist_ptr() as below(marked it with "^^^^"), which added the "swab()" operation, crash also needs to follow up this change, otherwise crash will get the error of "invalid freepointer". diff --git a/mm/slub.c b/mm/slub.c index fc911c222b11..bc949e3428c9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -259,7 +259,7 @@ static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr, * freepointer to be restored incorrectly. */ return (void *)((unsigned long)ptr ^ s->random ^ - (unsigned long)kasan_reset_tag((void *)ptr_addr)); + *swab*((unsigned long)kasan_reset_tag((void *)ptr_addr))); * ^^^^^* Before: crash> kmem -s CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME c0000000311a4200 152 0 0 0 64k fuse_request c0000000311a8700 800 0 0 0 64k fuse_inode c000000035df7600 528 0 0 0 64k xfs_dqtrx c000000035df6600 496 0 0 0 64k xfs_dquot kmem: xfs_buf: slab: c00c0000000b6500 invalid freepointer: 3808942d00004eb0 kmem: xfs_buf: slab: c00c00000116ba00 invalid freepointer: b83fe85a040027b0 ... After: crash> kmem -s CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME c0000000311a4200 152 0 0 0 64k fuse_request c0000000311a8700 800 0 0 0 64k fuse_inode c000000035df7600 528 0 0 0 64k xfs_dqtrx c000000035df6600 496 0 0 0 64k xfs_dquot c000000035dff500 360 7865 9010 53 64k xfs_buf ... Thanks. Lianbo