From: Nathan Chancellor natechancellor@gmail.com
mainline inclusion from mainline-5.7-rc1 commit 8755d97a09fed0de206772bcad1838301293c4d8 category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA ---------------------------
Clang warns:
fs/io_uring.c:4178:6: warning: variable 'mask' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (def->pollin) ^~~~~~~~~~~ fs/io_uring.c:4182:2: note: uninitialized use occurs here mask |= POLLERR | POLLPRI; ^~~~ fs/io_uring.c:4178:2: note: remove the 'if' if its condition is always true if (def->pollin) ^~~~~~~~~~~~~~~~ fs/io_uring.c:4154:15: note: initialize the variable 'mask' to silence this warning __poll_t mask, ret; ^ = 0 1 warning generated.
io_op_defs has many definitions where pollin is not set so mask indeed might be uninitialized. Initialize it to zero and change the next assignment to |=, in case further masks are added in the future to avoid missing changing the assignment then.
Fixes: d7718a9d25a6 ("io_uring: use poll driven retry for files that support it") Link: https://github.com/ClangBuiltLinux/linux/issues/916 Signed-off-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/io_uring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 6b0b5d6ad145..5a97d110602a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3690,8 +3690,9 @@ static bool io_arm_poll_handler(struct io_kiocb *req) req->apoll = apoll; INIT_HLIST_NODE(&req->hash_node);
+ mask = 0; if (def->pollin) - mask = POLLIN | POLLRDNORM; + mask |= POLLIN | POLLRDNORM; if (def->pollout) mask |= POLLOUT | POLLWRNORM; mask |= POLLERR | POLLPRI;