The patch titled
Subject: mm: fix racing of vb->va when kasan enabled
has been added to the -mm mm-unstable branch. Its filename is
mm-fix-racing-of-vb-va-when-kasan-enabled.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-fix-racing-of-vb-va-when-kasan-enabled.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
Subject: mm: fix racing of vb->va when kasan enabled
Date: Wed, 25 May 2022 10:52:44 +0800
Access to vb->va could be deemed as use after free when KASAN is enabled
like below. Fix it by expanding the mutex's range.
[ 20.232335] ==================================================================
[ 20.232365] BUG: KASAN: use-after-free in _vm_unmap_aliases+0x164/0x364
[ 20.232376] Read of size 8 at addr ffffff80d84af780 by task modprobe/300
[ 20.232380]
[ 20.232395] CPU: 5 PID: 300 Comm: modprobe Tainted: G S C O 5.4.161-android12-9-03238-gd43329d103de-ab20547 #1
[ 20.232401] Hardware name: Spreadtrum UMS512-1H10 SoC (DT)
[ 20.232407] Call trace:
[ 20.232419] dump_backtrace+0x0/0x2b4
[ 20.232428] show_stack+0x24/0x30
[ 20.232443] dump_stack+0x15c/0x1f4
[ 20.232455] print_address_description+0x88/0x568
[ 20.232465] __kasan_report+0x1b8/0x1dc
[ 20.232474] kasan_report+0x10/0x18
[ 20.232486] __asan_report_load8_noabort+0x1c/0x24
[ 20.232495] _vm_unmap_aliases+0x164/0x364
[ 20.232505] vm_unmap_aliases+0x20/0x28
[ 20.232516] change_memory_common+0x2c4/0x3ec
[ 20.232524] set_memory_ro+0x30/0x3c
[ 20.232539] module_enable_ro+0x144/0x3f0
[ 20.232547] load_module+0x54c0/0x8248
[ 20.232555] __se_sys_finit_module+0x174/0x1b0
[ 20.232564] __arm64_sys_finit_module+0x78/0x88
[ 20.232573] el0_svc_common+0x19c/0x354
[ 20.232581] el0_svc_handler+0x48/0x54
[ 20.232591] el0_svc+0x8/0xc
[ 20.232595]
[ 20.232602] Allocated by task 297:
[ 20.232615] __kasan_kmalloc+0x130/0x1f8
[ 20.232625] kasan_slab_alloc+0x14/0x1c
[ 20.232638] kmem_cache_alloc+0x1dc/0x394
[ 20.232648] alloc_vmap_area+0xb4/0x1630
[ 20.232657] vm_map_ram+0x3ac/0x768
[ 20.232671] z_erofs_decompress_generic+0x2f0/0x844
[ 20.232681] z_erofs_decompress+0xa8/0x594
[ 20.232692] z_erofs_decompress_pcluster+0xeb4/0x1458
[ 20.232702] z_erofs_vle_unzip_wq+0xe4/0x140
[ 20.232715] process_one_work+0x5c0/0x10ac
[ 20.232724] worker_thread+0x888/0x1128
[ 20.232733] kthread+0x290/0x304
[ 20.232744] ret_from_fork+0x10/0x18
[ 20.232747]
[ 20.232752] Freed by task 51:
[ 20.232762] __kasan_slab_free+0x1a0/0x270
[ 20.232772] kasan_slab_free+0x10/0x1c
[ 20.232781] slab_free_freelist_hook+0xd0/0x1ac
[ 20.232792] kmem_cache_free+0x110/0x368
[ 20.232803] __purge_vmap_area_lazy+0x524/0x13e4
[ 20.232813] _vm_unmap_aliases+0x290/0x364
[ 20.232822] __vunmap+0x45c/0x5c4
[ 20.232831] vfree+0x74/0x16c
[ 20.232841] module_memfree+0x44/0x7c
[ 20.232850] do_free_init+0x5c/0xac
[ 20.232860] process_one_work+0x5c0/0x10ac
[ 20.232869] worker_thread+0xb3c/0x1128
[ 20.232877] kthread+0x290/0x304
[ 20.232887] ret_from_fork+0x10/0x18
Link: https://lkml.kernel.org/r/1653447164-15017-1-git-send-email-zhaoyang.huang@xxxxxxxxxx
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
Cc: ke.wang <ke.wang@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/mm/vmalloc.c~mm-fix-racing-of-vb-va-when-kasan-enabled
+++ a/mm/vmalloc.c
@@ -2095,7 +2095,7 @@ static void _vm_unmap_aliases(unsigned l
return;
might_sleep();
-
+ mutex_lock(&vmap_purge_lock);
for_each_possible_cpu(cpu) {
struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
struct vmap_block *vb;
@@ -2120,7 +2120,6 @@ static void _vm_unmap_aliases(unsigned l
rcu_read_unlock();
}
- mutex_lock(&vmap_purge_lock);
purge_fragmented_blocks_allcpus();
if (!__purge_vmap_area_lazy(start, end) && flush)
flush_tlb_kernel_range(start, end);
_
Patches currently in -mm which might be from zhaoyang.huang@xxxxxxxxxx are
mm-fix-racing-of-vb-va-when-kasan-enabled.patch
