On 10/31/22 11:55, Anders Roxell wrote: > On 2022-10-28 08:53, Kees Cook wrote: >> Nothing appears to be using ksize() within the kmalloc-backed mempools >> except the mempool poisoning logic. Use the actual pool size instead >> of the ksize() to avoid needing any special handling of the memory as >> needed by KASAN, UBSAN_BOUNDS, nor FORTIFY_SOURCE. >> >> Suggested-by: Vlastimil Babka <vbabka@xxxxxxx> >> Link: https://lore.kernel.org/lkml/f4fc52c4-7c18-1d76-0c7a-4058ea2486b9@xxxxxxx/ >> Cc: David Rientjes <rientjes@xxxxxxxxxx> >> Cc: Marco Elver <elver@xxxxxxxxxx> >> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> Cc: linux-mm@xxxxxxxxx >> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> >> Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> >> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> >> --- >> This replaces mempool-use-kmalloc_size_roundup-to-match-ksize-usage.patch >> v4: add review/ack tags, explicitly call out subject change >> v3: https://lore.kernel.org/lkml/20221025233421.you.825-kees@xxxxxxxxxx/ >> v2: https://lore.kernel.org/lkml/20221018090323.never.897-kees@xxxxxxxxxx/ >> v1: https://lore.kernel.org/lkml/20220923202822.2667581-14-keescook@xxxxxxxxxxxx/ >> --- >> mm/mempool.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) > > Hi, > > I see the following kernel paninc when I boot an arm64 allmodconfig kernel from todays linux-next tag next-20221031 > This is the .config file I built [1], and here is the full log [2]. > > [ 17.445316][ T1] [fffe00001188f9bf] address between user and kernel address ranges > [ 17.449021][ T1] Internal error: Oops: 0000000096000044 [#1] PREEMPT SMP > [ 17.453097][ T1] Modules linked in: > [ 17.455384][ T1] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G B T 6.1.0-rc3-next-20221031 #2 1e3e4f9d63a6fa6d1a293981bef64866cf5e5454 > [ 17.463100][ T1] Hardware name: linux,dummy-virt (DT) > [ 17.466247][ T1] pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [ 17.470778][ T1] pc : __poison_element+0x3c/0x80 > [ 17.473688][ T1] lr : __poison_element+0x38/0x80 > [ 17.476614][ T1] sp : ffff80000eea7b50 > [ 17.478996][ T1] x29: ffff80000eea7b50 x28: ffff000008c88468 x27: ffff000008c88450 > [ 17.483694][ T1] x26: 0000000000000cc0 x25: ffff000008c88448 x24: ffff000008b3cf80 > [ 17.488338][ T1] x23: ffff000008c8844c x22: ffff000008c88460 x21: ffff000008d52a40 > [ 17.493032][ T1] x20: ffff000008d52a40 x19: ffff000008b3cf7f x18: 0000000000000000 > [ 17.497707][ T1] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > [ 17.502413][ T1] x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001 > [ 17.507109][ T1] x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 > [ 17.511775][ T1] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 > [ 17.516447][ T1] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 > [ 17.521116][ T1] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 00000000ffffffa5 > [ 17.525782][ T1] Call trace: > [ 17.527664][ T1] __poison_element+0x3c/0x80 > [ 17.530409][ T1] poison_element.isra.0+0x50/0x180 > [ 17.533419][ T1] mempool_init_node+0x224/0x340 > [ 17.536298][ T1] mempool_create+0x78/0x100 > [ 17.538989][ T1] dma_bus_init+0x124/0x2a4 > [ 17.541607][ T1] do_one_initcall+0x29c/0x680 > [ 17.544381][ T1] do_initcalls+0x178/0x240 > [ 17.547005][ T1] kernel_init_freeable+0x2e4/0x36c > [ 17.550018][ T1] kernel_init+0x30/0x180 > [ 17.552534][ T1] ret_from_fork+0x10/0x20 > [ 17.555130][ T1] Code: 94057fb5 8b130280 940575a3 12800b40 > (38336a80) > [ 17.559124][ T1] ---[ end trace 0000000000000000 ]--- > [ 17.562259][ T1] Kernel panic - not syncing: Oops: Fatal exception > [ 17.566094][ T1] ---[ end Kernel panic - not syncing: Oops: Fatal exception ]--- > > When I revert this patch the kernel boots fine. > Any idea what goes wrong? Oops, I think I know, this should fix it? ----8<---- >From a4a5a40852723dfadb2429bee1d5e1f9d3b75f39 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka <vbabka@xxxxxxx> Date: Mon, 31 Oct 2022 15:55:47 +0100 Subject: [PATCH] mempool: Do not use ksize() for poisoning-fix For slab mempools (not kmalloc), pool_data is not object size, but a kmem_cache pointer; we need to extract the size via kmem_cache_size(). Reported-by: Anders Roxell <anders.roxell@xxxxxxxxxx> Link: https://lore.kernel.org/all/20221031105514.GB69385@mutt/ Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Link: https://lore.kernel.org/oe-lkp/202210312110.1fe5d224-oliver.sang@xxxxxxxxx Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> --- mm/mempool.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/mm/mempool.c b/mm/mempool.c index 54204065037d..734bcf5afbb7 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -57,8 +57,10 @@ static void __check_element(mempool_t *pool, void *element, size_t size) static void check_element(mempool_t *pool, void *element) { /* Mempools backed by slab allocator */ - if (pool->free == mempool_free_slab || pool->free == mempool_kfree) { + if (pool->free == mempool_kfree) { __check_element(pool, element, (size_t)pool->pool_data); + } else if (pool->free == mempool_free_slab) { + __check_element(pool, element, kmem_cache_size(pool->pool_data)); } else if (pool->free == mempool_free_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; @@ -80,8 +82,10 @@ static void __poison_element(void *element, size_t size) static void poison_element(mempool_t *pool, void *element) { /* Mempools backed by slab allocator */ - if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) { + if (pool->alloc == mempool_kmalloc) { __poison_element(element, (size_t)pool->pool_data); + } else if (pool->alloc == mempool_alloc_slab) { + __poison_element(element, kmem_cache_size(pool->pool_data)); } else if (pool->alloc == mempool_alloc_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; @@ -111,8 +115,10 @@ static __always_inline void kasan_poison_element(mempool_t *pool, void *element) static void kasan_unpoison_element(mempool_t *pool, void *element) { - if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) + if (pool->alloc == mempool_kmalloc) kasan_unpoison_range(element, (size_t)pool->pool_data); + else if (pool->alloc == mempool_alloc_slab) + kasan_unpoison_range(element, kmem_cache_size(pool->pool_data)); else if (pool->alloc == mempool_alloc_pages) kasan_unpoison_pages(element, (unsigned long)pool->pool_data, false); -- 2.38.0
