From bee20031772af3debe8cbaa234528f24c7892e8f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 19 Jun 2018 13:14:57 -0700 Subject: disable -Wattribute-alias warning for SYSCALL_DEFINEx() gcc-8 warns for every single definition of a system call entry point, e.g.: include/linux/compat.h:56:18: error: 'compat_sys_rt_sigprocmask' alias between functions of incompatible types 'long int(int, compat_sigset_t *, compat_sigset_t *, compat_size_t)' {aka 'long int(int, struct *, struct *, unsigned int)'} and 'long int(long int, long int, long int, long int)' [-Werror=attribute-alias] asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\ ^~~~~~~~~~ include/linux/compat.h:45:2: note: in expansion of macro 'COMPAT_SYSCALL_DEFINEx' COMPAT_SYSCALL_DEFINEx(4, _##name, __VA_ARGS__) ^~~~~~~~~~~~~~~~~~~~~~ kernel/signal.c:2601:1: note: in expansion of macro 'COMPAT_SYSCALL_DEFINE4' COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset, ^~~~~~~~~~~~~~~~~~~~~~ include/linux/compat.h:60:18: note: aliased declaration here asmlinkage long compat_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__))\ ^~~~~~~~~~ The new warning seems reasonable in principle, but it doesn't help us here, since we rely on the type mismatch to sanitize the system call arguments. After I reported this as GCC PR82435, a new -Wno-attribute-alias option was added that could be used to turn the warning off globally on the command line, but I'd prefer to do it a little more fine-grained. Interestingly, turning a warning off and on again inside of a single macro doesn't always work, in this case I had to add an extra statement inbetween and decided to copy the __SC_TEST one from the native syscall to the compat syscall macro. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 for more details about this. [paul.burton@mips.com: - Rebase atop current master. - Split GCC & version arguments to __diag_ignore() in order to match changes to the preceding patch. - Add the comment argument to match the preceding patch.] Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82435 Signed-off-by: Arnd Bergmann Signed-off-by: Paul Burton Tested-by: Christophe Leroy Tested-by: Stafford Horne Signed-off-by: Masahiro Yamada --- include/linux/syscalls.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/syscalls.h') diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 73810808cdf2..a368a68cb667 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -231,6 +231,9 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) */ #ifndef __SYSCALL_DEFINEx #define __SYSCALL_DEFINEx(x, name, ...) \ + __diag_push(); \ + __diag_ignore(GCC, 8, "-Wattribute-alias", \ + "Type aliasing is used to sanitize syscall arguments");\ asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \ __attribute__((alias(__stringify(__se_sys##name)))); \ ALLOW_ERROR_INJECTION(sys##name, ERRNO); \ @@ -243,6 +246,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \ return ret; \ } \ + __diag_pop(); \ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) #endif /* __SYSCALL_DEFINEx */ -- cgit v1.2.3 From 9ba546c01976a426292af99e682a557075d6c010 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 11 Jul 2018 15:48:46 +0200 Subject: aio: don't expose __aio_sigset in uapi glibc uses a different defintion of sigset_t than the kernel does, and the current version would pull in both. To fix this just do not expose the type at all - this somewhat mirrors pselect() where we do not even have a type for the magic sigmask argument, but just use pointer arithmetics. Fixes: 7a074e96 ("aio: implement io_pgetevents") Signed-off-by: Christoph Hellwig Reported-by: Adrian Reber Signed-off-by: Al Viro --- fs/aio.c | 5 +++++ include/linux/syscalls.h | 1 + include/uapi/linux/aio_abi.h | 6 ------ 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'include/linux/syscalls.h') diff --git a/fs/aio.c b/fs/aio.c index e1d20124ec0e..b1a42e45698b 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -2042,6 +2042,11 @@ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, return ret; } +struct __aio_sigset { + const sigset_t __user *sigmask; + size_t sigsetsize; +}; + SYSCALL_DEFINE6(io_pgetevents, aio_context_t, ctx_id, long, min_nr, diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 73810808cdf2..b06b5eeda8e8 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -11,6 +11,7 @@ #ifndef _LINUX_SYSCALLS_H #define _LINUX_SYSCALLS_H +struct __aio_sigset; struct epoll_event; struct iattr; struct inode; diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h index d00221345c19..ce43d340f010 100644 --- a/include/uapi/linux/aio_abi.h +++ b/include/uapi/linux/aio_abi.h @@ -29,7 +29,6 @@ #include #include -#include #include typedef __kernel_ulong_t aio_context_t; @@ -108,10 +107,5 @@ struct iocb { #undef IFBIG #undef IFLITTLE -struct __aio_sigset { - const sigset_t __user *sigmask; - size_t sigsetsize; -}; - #endif /* __LINUX__AIO_ABI_H */ -- cgit v1.2.3