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authorGuenter Roeck <linux@roeck-us.net>2022-06-01 01:29:51 +0300
committerakpm <akpm@linux-foundation.org>2022-06-17 05:58:20 +0300
commit0cc011c576aaa4de505046f7a6c90933d7c749a9 (patch)
tree8ca5e4ecd17087ab745b2e65cef0973ad749c351 /lib/list_debug.c
parent53fd5ffbb5197b8cc2d73d2bbc0f688afd45736c (diff)
downloadlinux-0cc011c576aaa4de505046f7a6c90933d7c749a9.tar.xz
lib/list_debug.c: Detect uninitialized lists
In some circumstances, attempts are made to add entries to or to remove entries from an uninitialized list. A prime example is amdgpu_bo_vm_destroy(): It is indirectly called from ttm_bo_init_reserved() if that function fails, and tries to remove an entry from a list. However, that list is only initialized in amdgpu_bo_create_vm() after the call to ttm_bo_init_reserved() returned success. This results in crashes such as BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 1479 Comm: chrome Not tainted 5.10.110-15768-g29a72e65dae5 Hardware name: Google Grunt/Grunt, BIOS Google_Grunt.11031.149.0 07/15/2020 RIP: 0010:__list_del_entry_valid+0x26/0x7d ... Call Trace: amdgpu_bo_vm_destroy+0x48/0x8b ttm_bo_init_reserved+0x1d7/0x1e0 amdgpu_bo_create+0x212/0x476 ? amdgpu_bo_user_destroy+0x23/0x23 ? kmem_cache_alloc+0x60/0x271 amdgpu_bo_create_vm+0x40/0x7d amdgpu_vm_pt_create+0xe8/0x24b ... Check if the list's prev and next pointers are NULL to catch such problems. Link: https://lkml.kernel.org/r/20220531222951.92073-1-linux@roeck-us.net Signed-off-by: Guenter Roeck <linux@roeck-us.net> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/list_debug.c')
-rw-r--r--lib/list_debug.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/lib/list_debug.c b/lib/list_debug.c
index 9daa3fb9d1cd..d98d43f80958 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -20,7 +20,11 @@
bool __list_add_valid(struct list_head *new, struct list_head *prev,
struct list_head *next)
{
- if (CHECK_DATA_CORRUPTION(next->prev != prev,
+ if (CHECK_DATA_CORRUPTION(prev == NULL,
+ "list_add corruption. prev is NULL.\n") ||
+ CHECK_DATA_CORRUPTION(next == NULL,
+ "list_add corruption. next is NULL.\n") ||
+ CHECK_DATA_CORRUPTION(next->prev != prev,
"list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n",
prev, next->prev, next) ||
CHECK_DATA_CORRUPTION(prev->next != next,
@@ -42,7 +46,11 @@ bool __list_del_entry_valid(struct list_head *entry)
prev = entry->prev;
next = entry->next;
- if (CHECK_DATA_CORRUPTION(next == LIST_POISON1,
+ if (CHECK_DATA_CORRUPTION(next == NULL,
+ "list_del corruption, %px->next is NULL\n", entry) ||
+ CHECK_DATA_CORRUPTION(prev == NULL,
+ "list_del corruption, %px->prev is NULL\n", entry) ||
+ CHECK_DATA_CORRUPTION(next == LIST_POISON1,
"list_del corruption, %px->next is LIST_POISON1 (%px)\n",
entry, LIST_POISON1) ||
CHECK_DATA_CORRUPTION(prev == LIST_POISON2,