Hi Jens,

FYI, the error/warning still remains.

tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: 07d14ba27c5232baa4db34abda2725802e5cab3c commit: 6c08191286995b0594d2ecf12fe7fca3cea1a5ca [1353/1353] io_uring: add support for pre-mapped user IO buffers config: arm64-randconfig-001-20241225 (https://download.01.org/0day-ci/archive/20241226/202412260313.PaIUDFJt-lkp@i...) compiler: aarch64-linux-gcc (GCC) 14.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241226/202412260313.PaIUDFJt-lkp@i...)

If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202412260313.PaIUDFJt-lkp@intel.com/

Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

In file included from include/linux/poll.h:12, from include/linux/ring_buffer.h:7, from include/linux/trace_events.h:6, from include/trace/syscall.h:7, from include/linux/syscalls.h:86, from fs/io_uring.c:32: In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'io_copy_iov.isra' at fs/io_uring.c:1457:7:

...

include/linux/uaccess.h:112:17: warning: 'ciov' may be used uninitialized [-Wmaybe-uninitialized]

112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/compiler.h:251, from include/linux/export.h:45, from include/linux/linkage.h:7, from include/linux/kernel.h:7, from fs/io_uring.c:29: include/linux/kasan-checks.h: In function 'io_copy_iov.isra': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ fs/io_uring.c:1454:37: note: 'ciov' declared here 1454 | struct compat_iovec ciov; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'io_uring_setup' at fs/io_uring.c:1960:6: include/linux/uaccess.h:112:17: warning: 'p' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'io_uring_setup': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ fs/io_uring.c:1956:32: note: 'p' declared here 1956 | struct io_uring_params p; | ^ In file included from include/linux/uaccess.h:11: In function 'set_fs', inlined from 'io_sq_wq_submit_work' at fs/io_uring.c:1114:3: arch/arm64/include/asm/uaccess.h:59:12: warning: 'old_fs' may be used uninitialized [-Wmaybe-uninitialized] 59 | if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS) | ^ fs/io_uring.c: In function 'io_sq_wq_submit_work': fs/io_uring.c:1074:22: note: 'old_fs' was declared here 1074 | mm_segment_t old_fs; | ^~~~~~

vim +/ciov +112 include/linux/uaccess.h

d597580d373774 Al Viro 2017-03-20 104 d597580d373774 Al Viro 2017-03-20 105 #ifdef INLINE_COPY_FROM_USER d597580d373774 Al Viro 2017-03-20 106 static inline unsigned long d597580d373774 Al Viro 2017-03-20 107 _copy_from_user(void *to, const void __user *from, unsigned long n) d597580d373774 Al Viro 2017-03-20 108 { d597580d373774 Al Viro 2017-03-20 109 unsigned long res = n; 9c5f6908de03a4 Al Viro 2017-06-29 110 might_fault(); 4983cb67a383a7 Linus Torvalds 2019-02-14 111 if (likely(access_ok(from, n))) { 9c5f6908de03a4 Al Viro 2017-06-29 @112 kasan_check_write(to, n); d597580d373774 Al Viro 2017-03-20 113 res = raw_copy_from_user(to, from, n); 9c5f6908de03a4 Al Viro 2017-06-29 114 } d597580d373774 Al Viro 2017-03-20 115 if (unlikely(res)) d597580d373774 Al Viro 2017-03-20 116 memset(to + (n - res), 0, res); d597580d373774 Al Viro 2017-03-20 117 return res; d597580d373774 Al Viro 2017-03-20 118 } d597580d373774 Al Viro 2017-03-20 119 #else d597580d373774 Al Viro 2017-03-20 120 extern unsigned long d597580d373774 Al Viro 2017-03-20 121 _copy_from_user(void *, const void __user *, unsigned long); d597580d373774 Al Viro 2017-03-20 122 #endif d597580d373774 Al Viro 2017-03-20 123

:::::: The code at line 112 was first introduced by commit :::::: 9c5f6908de03a4f52ba7364b11fcd6116225480c copy_{from,to}_user(): move kasan checks and might_fault() out-of-line

:::::: TO: Al Viro viro@zeniv.linux.org.uk :::::: CC: Al Viro viro@zeniv.linux.org.uk