From d0f788b8fab24197232a6753c3f556ee0cc9d039 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 11 Jan 2023 14:46:15 +0000 Subject: [PATCH] ANDROID: struct io_uring ABI preservation hack for 5.10.162 changes In the 5.10.162 release, the io_uring code was synced with the version that is in the 5.15.y kernel tree in order to resolve a huge number of potential, and known, problems with the codebase. This makes for a more secure and easier-to-update-and-maintain 5.10.y kernel tree, so this is a great thing, however this caused some issues when it comes to the Android KABI preservation and checking tools. A number of the io_uring structures get used in other core kernel structures, only as "opaque" pointers, so there is not any real ABI breakage. But, due to the visibility of the structures going away, the CRC values of many scheduler variables and functions were changed. In order to preserve the CRC values, to prevent all device kernels to be forced to rebuild for no reason whatsoever from a functional point of view, we need to keep around the "old" io_uring structures for the CRC calculation only. This is done by the following definitions of struct io_identity and struct io_uring_task which will only be visible when the CRC calculation build happens, not in any functional kernel build. Yes, this all is a horrible hack, and these really are not the true structures that any code uses, but so life is in the world of stable apis. Bug: 161946584 Bug: 268174392 Fixes: 788d0824269b ("io_uring: import 5.15-stable io_uring") Signed-off-by: Greg Kroah-Hartman Change-Id: I2294f220ae78fe9aa32ee25b81829ae765e9deb2 --- include/linux/io_uring.h | 62 ++++++++++++++++++++++++++++++++++++++++ io_uring/io-wq.h | 11 +++++++ io_uring/io_uring.c | 10 +++++++ 3 files changed, 83 insertions(+) diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h index 649a4d7c241b..5ae871af45de 100644 --- a/include/linux/io_uring.h +++ b/include/linux/io_uring.h @@ -5,6 +5,68 @@ #include #include +#ifdef __GENKSYMS__ +/* + * ANDROID ABI HACK + * + * In the 5.10.162 release, the io_uring code was synced with the version + * that is in the 5.15.y kernel tree in order to resolve a huge number of + * potential, and known, problems with the codebase. This makes for a more + * secure and easier-to-update-and-maintain 5.10.y kernel tree, so this is + * a great thing, however this caused some issues when it comes to the + * Android KABI preservation and checking tools. + * + * A number of the io_uring structures get used in other core kernel + * structures, only as "opaque" pointers, so there is not any real ABI + * breakage. But, due to the visibility of the structures going away, the + * CRC values of many scheduler variables and functions were changed. + * + * In order to preserve the CRC values, to prevent all device kernels to be + * forced to rebuild for no reason whatsoever from a functional point of + * view, we need to keep around the "old" io_uring structures for the CRC + * calculation only. This is done by the following definitions of struct + * io_identity and struct io_uring_task which will only be visible when the + * CRC calculation build happens, not in any functional kernel build. + * + * Yes, this all is a horrible hack, and these really are not the true + * structures that any code uses, but so life is in the world of stable + * apis... + * The real structures are in io_uring/io_uring.c, see the ones there if + * you need to touch or do anything with it. + * + * NEVER touch these structure definitions, they are fake and not valid code. + */ +struct io_identity { + struct files_struct *files; + struct mm_struct *mm; +#ifdef CONFIG_BLK_CGROUP + struct cgroup_subsys_state *blkcg_css; +#endif + const struct cred *creds; + struct nsproxy *nsproxy; + struct fs_struct *fs; + unsigned long fsize; +#ifdef CONFIG_AUDIT + kuid_t loginuid; + unsigned int sessionid; +#endif + refcount_t count; +}; + +struct io_uring_task { + /* submission side */ + struct xarray xa; + struct wait_queue_head wait; + struct file *last; + struct percpu_counter inflight; + struct io_identity __identity; + struct io_identity *identity; + atomic_t in_idle; + bool sqpoll; +}; +#endif /* ANDROID ABI HACK */ + + #if defined(CONFIG_IO_URING) struct sock *io_uring_get_socket(struct file *file); void __io_uring_cancel(bool cancel_all); diff --git a/io_uring/io-wq.h b/io_uring/io-wq.h index bf5c4c533760..300a695d191d 100644 --- a/io_uring/io-wq.h +++ b/io_uring/io-wq.h @@ -1,6 +1,17 @@ #ifndef INTERNAL_IO_WQ_H #define INTERNAL_IO_WQ_H +#ifdef __GENKSYMS__ +/* + * ANDROID ABI HACK + * + * See the big comment in the linux/io_uring.h file for details. This + * include is not needed for any real functionality, but must be here to + * preserve the CRC of a number of variables and functions. + */ +#include +#endif + #include struct io_wq; diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 945faf036ad0..35a9bcd5648b 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -461,6 +461,15 @@ struct io_ring_ctx { }; }; +#ifndef __GENKSYMS__ +/* + * ANDROID ABI HACK + * + * See the big comment in the linux/io_uring.h file for details. This + * structure definition should NOT be used if __GENKSYMS__ is enabled, + * as a "fake" structure definition has already been read in the + * linux/io_uring.h file in order to preserve the Android kernel ABI. + */ struct io_uring_task { /* submission side */ int cached_refs; @@ -477,6 +486,7 @@ struct io_uring_task { struct callback_head task_work; bool task_running; }; +#endif /* * First field must be the file pointer in all the