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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>
This commit is contained in:
Guenter Roeck 2022-05-31 15:29:51 -07:00 committed by akpm
parent 53fd5ffbb5
commit 0cc011c576
1 changed files with 10 additions and 2 deletions
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12
lib/list_debug.c
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@ -20,7 +20,11 @@
bool __list_add_valid(struct list_head *new, struct list_head *prev, bool __list_add_valid(struct list_head *new, struct list_head *prev,
struct list_head *next) 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", "list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n",
prev, next->prev, next) || prev, next->prev, next) ||
CHECK_DATA_CORRUPTION(prev->next != next, CHECK_DATA_CORRUPTION(prev->next != next,
@ -42,7 +46,11 @@ bool __list_del_entry_valid(struct list_head *entry)
prev = entry->prev; prev = entry->prev;
next = entry->next; 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", "list_del corruption, %px->next is LIST_POISON1 (%px)\n",
entry, LIST_POISON1) || entry, LIST_POISON1) ||
CHECK_DATA_CORRUPTION(prev == LIST_POISON2, CHECK_DATA_CORRUPTION(prev == LIST_POISON2,