Gitlab 现已全面支持 git over ssh 与 git over https。通过 HTTPS 访问请配置带有 read_repository / write_repository 权限的 Personal access token。通过 SSH 端口访问请使用 22 端口或 13389 端口。如果使用CAS注册了账户但不知道密码，可以自行至设置中更改；如有其他问题，请发邮件至 service@cra.moe 寻求协助。

Commit 31b90956 authored Jun 10, 2019 by Coly Li Committed by Jens Axboe Jun 13, 2019

bcache: fix stack corruption by PRECEDING_KEY()



Recently people report bcache code compiled with gcc9 is broken, one of
the buggy behavior I observe is that two adjacent 4KB I/Os should merge
into one but they don't. Finally it turns out to be a stack corruption
caused by macro PRECEDING_KEY().

See how PRECEDING_KEY() is defined in bset.h,
437 #define PRECEDING_KEY(_k)                                       \
438 ({                                                              \
439         struct bkey *_ret = NULL;                               \
440                                                                 \
441         if (KEY_INODE(_k) || KEY_OFFSET(_k)) {                  \
442                 _ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0);  \
443                                                                 \
444                 if (!_ret->low)                                 \
445                         _ret->high--;                           \
446                 _ret->low--;                                    \
447         }                                                       \
448                                                                 \
449         _ret;                                                   \
450 })

At line 442, _ret points to address of a on-stack variable combined by
KEY(), the life range of this on-stack variable is in line 442-446,
once _ret is returned to bch_btree_insert_key(), the returned address
points to an invalid stack address and this address is overwritten in
the following called bch_btree_iter_init(). Then argument 'search' of
bch_btree_iter_init() points to some address inside stackframe of
bch_btree_iter_init(), exact address depends on how the compiler
allocates stack space. Now the stack is corrupted.

Fixes: 0eacac22 ("bcache: PRECEDING_KEY()")
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Rolf Fokkens <rolf@rolffokkens.nl>
Reviewed-by: Pierre JUHEN <pierre.juhen@orange.fr>
Tested-by: Shenghui Wang <shhuiw@foxmail.com>
Tested-by: Pierre JUHEN <pierre.juhen@orange.fr>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Nix <nix@esperi.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent c326f846

drivers/md/bcache/bset.c

+13 −3

Original line number	Diff line number	Diff line
		@@ -887,12 +887,22 @@ unsigned int bch_btree_insert_key(struct btree_keys b, struct bkey k,
		struct bset *i = bset_tree_last(b)->data;
		struct bkey m, prev = NULL;
		struct btree_iter iter;
		struct bkey preceding_key_on_stack = ZERO_KEY;
		struct bkey *preceding_key_p = &preceding_key_on_stack;

		BUG_ON(b->ops->is_extents && !KEY_SIZE(k));

		m = bch_btree_iter_init(b, &iter, b->ops->is_extents
		? PRECEDING_KEY(&START_KEY(k))
		: PRECEDING_KEY(k));
		/*
		* If k has preceding key, preceding_key_p will be set to address
		* of k's preceding key; otherwise preceding_key_p will be set
		* to NULL inside preceding_key().
		*/
		if (b->ops->is_extents)
		preceding_key(&START_KEY(k), &preceding_key_p);
		else
		preceding_key(k, &preceding_key_p);

		m = bch_btree_iter_init(b, &iter, preceding_key_p);

		if (b->ops->insert_fixup(b, k, &iter, replace_key))
		return status;

drivers/md/bcache/bset.h

+20 −14

Original line number	Diff line number	Diff line
		@@ -434,20 +434,26 @@ static inline bool bch_cut_back(const struct bkey where, struct bkey k)
		return __bch_cut_back(where, k);
		}

		#define PRECEDING_KEY(_k) \
		({ \
		struct bkey *_ret = NULL; \
		\
		if (KEY_INODE(_k) \|\| KEY_OFFSET(_k)) { \
		_ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0); \
		\
		if (!_ret->low) \
		_ret->high--; \
		_ret->low--; \
		} \
		\
		_ret; \
		})
		/*
		* Pointer '*preceding_key_p' points to a memory object to store preceding
		* key of k. If the preceding key does not exist, set '*preceding_key_p' to
		* NULL. So the caller of preceding_key() needs to take care of memory
		* which '*preceding_key_p' pointed to before calling preceding_key().
		* Currently the only caller of preceding_key() is bch_btree_insert_key(),
		* and it points to an on-stack variable, so the memory release is handled
		* by stackframe itself.
		*/
		static inline void preceding_key(struct bkey k, struct bkey *preceding_key_p)
		{
		if (KEY_INODE(k) \|\| KEY_OFFSET(k)) {
		(**preceding_key_p) = KEY(KEY_INODE(k), KEY_OFFSET(k), 0);
		if (!(*preceding_key_p)->low)
		(*preceding_key_p)->high--;
		(*preceding_key_p)->low--;
		} else {
		(*preceding_key_p) = NULL;
		}
		}

		static inline bool bch_ptr_invalid(struct btree_keys b, const struct bkey k)
		{

CRA Git | Maintained and supported by SUSTech CRA and CCSE