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authorLinus Torvalds <torvalds@linux-foundation.org>2021-09-14 13:23:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-14 13:23:22 -0700
commit77e02cf57b6cff9919949defb7fd9b8ac16399a2 (patch)
tree96d0a1d317e28e7b22165ca419c99f7313e64ea3 /lib/bootconfig.c
parent6a4746ba06191e23d30230738e94334b26590a8a (diff)
memblock: introduce saner 'memblock_free_ptr()' interface
The boot-time allocation interface for memblock is a mess, with 'memblock_alloc()' returning a virtual pointer, but then you are supposed to free it with 'memblock_free()' that takes a _physical_ address. Not only is that all kinds of strange and illogical, but it actually causes bugs, when people then use it like a normal allocation function, and it fails spectacularly on a NULL pointer: https://lore.kernel.org/all/20210912140820.GD25450@xsang-OptiPlex-9020/ or just random memory corruption if the debug checks don't catch it: https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@suse.cz/ I really don't want to apply patches that treat the symptoms, when the fundamental cause is this horribly confusing interface. I started out looking at just automating a sane replacement sequence, but because of this mix or virtual and physical addresses, and because people have used the "__pa()" macro that can take either a regular kernel pointer, or just the raw "unsigned long" address, it's all quite messy. So this just introduces a new saner interface for freeing a virtual address that was allocated using 'memblock_alloc()', and that was kept as a regular kernel pointer. And then it converts a couple of users that are obvious and easy to test, including the 'xbc_nodes' case in lib/bootconfig.c that caused problems. Reported-by: kernel test robot <oliver.sang@intel.com> Fixes: 40caa127f3c7 ("init: bootconfig: Remove all bootconfig data when the init memory is removed") Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/bootconfig.c')
-rw-r--r--lib/bootconfig.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index f8419cff1147..5ae248b29373 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -792,7 +792,7 @@ void __init xbc_destroy_all(void)
xbc_data = NULL;
xbc_data_size = 0;
xbc_node_num = 0;
- memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
+ memblock_free_ptr(xbc_nodes, sizeof(struct xbc_node) * XBC_NODE_MAX);
xbc_nodes = NULL;
brace_index = 0;
}