From: Andrii Nakryiko <andrii@xxxxxxxxxx> commit d699440f58ce9bd71103cc7b692e3ab76a20bfcd upstream. When vrealloc() reuses already allocated vmap_area, we need to re-annotate poisoned and unpoisoned portions of underlying memory according to the new size. This results in a KASAN splat recorded at [1]. A KASAN mis-reporting issue where there is none. Note, hard-coding KASAN_VMALLOC_PROT_NORMAL might not be exactly correct, but KASAN flag logic is pretty involved and spread out throughout __vmalloc_node_range_noprof(), so I'm using the bare minimum flag here and leaving the rest to mm people to refactor this logic and reuse it here. Link: https://lkml.kernel.org/r/20241126005206.3457974-1-andrii@xxxxxxxxxx Link: https://lore.kernel.org/bpf/67450f9b.050a0220.21d33d.0004.GAE@xxxxxxxxxx/ [1] Fixes: 3ddc2fefe6f3 ("mm: vmalloc: implement vrealloc()") Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 7ed39d104201..f009b21705c1 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4093,7 +4093,8 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags) /* Zero out spare memory. */ if (want_init_on_alloc(flags)) memset((void *)p + size, 0, old_size - size); - + kasan_poison_vmalloc(p + size, old_size - size); + kasan_unpoison_vmalloc(p, size, KASAN_VMALLOC_PROT_NORMAL); return (void *)p; } -- 2.47.1 Patches currently in stable-queue which might be from andrii@xxxxxxxxxx are queue-6.12/mm-fix-vrealloc-s-kasan-poisoning-logic.patch queue-6.12/bpf-don-t-mark-stack_invalid-as-stack_misc-in-mark_s.patch queue-6.12/bpf-fix-narrow-scalar-spill-onto-64-bit-spilled-scal.patch queue-6.12/bpf-ensure-reg-is-ptr_to_stack-in-process_iter_arg.patch
