Hi Darrick, [auto build test WARNING on linus/master] [also build test WARNING on v4.9-rc8 next-20161206] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Darrick-J-Wong/vfs-reject-inodes-with-negative-size-to-prevent-kernel-hang/20161207-110513 config: i386-randconfig-s1-201649 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=i386 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 >>): Cyclomatic Complexity 1 fs/dcache.c:__d_rehash Cyclomatic Complexity 2 fs/dcache.c:prepend Cyclomatic Complexity 3 fs/dcache.c:path_with_deleted Cyclomatic Complexity 7 fs/dcache.c:__dentry_path Cyclomatic Complexity 1 fs/dcache.c:prepend_unreachable Cyclomatic Complexity 4 fs/dcache.c:d_shrink_del Cyclomatic Complexity 4 fs/dcache.c:d_shrink_add Cyclomatic Complexity 2 fs/dcache.c:__d_instantiate Cyclomatic Complexity 7 fs/dcache.c:d_lru_add Cyclomatic Complexity 2 fs/dcache.c:dentry_lru_add Cyclomatic Complexity 7 fs/dcache.c:d_lru_del Cyclomatic Complexity 7 fs/dcache.c:select_collect Cyclomatic Complexity 2 fs/dcache.c:detach_and_collect Cyclomatic Complexity 6 fs/dcache.c:dentry_unlink_inode Cyclomatic Complexity 1 fs/dcache.c:__d_free_external Cyclomatic Complexity 1 fs/dcache.c:__d_free Cyclomatic Complexity 5 fs/dcache.c:dentry_free Cyclomatic Complexity 4 fs/dcache.c:d_lru_isolate Cyclomatic Complexity 4 fs/dcache.c:d_lru_shrink_move Cyclomatic Complexity 4 fs/dcache.c:dentry_lru_isolate Cyclomatic Complexity 2 fs/dcache.c:dentry_lru_isolate_shrink Cyclomatic Complexity 16 fs/dcache.c:d_walk Cyclomatic Complexity 6 fs/dcache.c:umount_check Cyclomatic Complexity 3 fs/dcache.c:d_wait_lookup Cyclomatic Complexity 6 fs/dcache.c:swap_names Cyclomatic Complexity 6 fs/dcache.c:copy_name Cyclomatic Complexity 2 fs/dcache.c:set_dhash_entries Cyclomatic Complexity 1 fs/dcache.c:vfs_caches_init_early Cyclomatic Complexity 1 fs/dcache.c:vfs_caches_init Cyclomatic Complexity 1 fs/dcache.c:proc_nr_dentry Cyclomatic Complexity 3 fs/dcache.c:__d_drop Cyclomatic Complexity 11 fs/dcache.c:__dentry_kill Cyclomatic Complexity 6 fs/dcache.c:dentry_kill Cyclomatic Complexity 16 fs/dcache.c:shrink_dentry_list Cyclomatic Complexity 3 fs/dcache.c:check_and_drop Cyclomatic Complexity 1 fs/dcache.c:d_drop Cyclomatic Complexity 10 fs/dcache.c:dput Cyclomatic Complexity 4 fs/dcache.c:dget_parent Cyclomatic Complexity 2 fs/dcache.c:d_find_alias Cyclomatic Complexity 7 fs/dcache.c:d_prune_aliases Cyclomatic Complexity 1 fs/dcache.c:prune_dcache_sb Cyclomatic Complexity 6 fs/dcache.c:shrink_dcache_sb Cyclomatic Complexity 1 fs/dcache.c:have_submounts Cyclomatic Complexity 4 fs/dcache.c:d_set_mounted Cyclomatic Complexity 2 fs/dcache.c:shrink_dcache_parent Cyclomatic Complexity 1 fs/dcache.c:do_one_tree Cyclomatic Complexity 3 fs/dcache.c:shrink_dcache_for_umount Cyclomatic Complexity 7 fs/dcache.c:d_invalidate Cyclomatic Complexity 15 fs/dcache.c:d_set_d_op Cyclomatic Complexity 9 fs/dcache.c:__d_alloc Cyclomatic Complexity 2 fs/dcache.c:d_alloc Cyclomatic Complexity 1 fs/dcache.c:d_alloc_name Cyclomatic Complexity 2 fs/dcache.c:d_alloc_cursor Cyclomatic Complexity 1 fs/dcache.c:d_alloc_pseudo Cyclomatic Complexity 1 fs/dcache.c:d_set_fallthru Cyclomatic Complexity 2 fs/dcache.c:d_instantiate Cyclomatic Complexity 3 fs/dcache.c:d_instantiate_no_diralias Cyclomatic Complexity 3 fs/dcache.c:d_make_root Cyclomatic Complexity 1 fs/dcache.c:d_find_any_alias Cyclomatic Complexity 7 fs/dcache.c:__d_obtain_alias Cyclomatic Complexity 1 fs/dcache.c:d_obtain_alias Cyclomatic Complexity 1 fs/dcache.c:d_obtain_root Cyclomatic Complexity 11 fs/dcache.c:__d_lookup_rcu Cyclomatic Complexity 7 fs/dcache.c:__d_lookup Cyclomatic Complexity 3 fs/dcache.c:d_lookup Cyclomatic Complexity 3 fs/dcache.c:d_hash_and_lookup Cyclomatic Complexity 4 fs/dcache.c:d_delete Cyclomatic Complexity 1 fs/dcache.c:d_rehash Cyclomatic Complexity 18 fs/dcache.c:d_alloc_parallel Cyclomatic Complexity 1 fs/dcache.c:__d_lookup_done Cyclomatic Complexity 2 fs/dcache.c:d_add Cyclomatic Complexity 8 fs/dcache.c:d_exact_alias Cyclomatic Complexity 1 fs/dcache.c:dentry_update_name_case Cyclomatic Complexity 3 fs/dcache.c:d_ancestor Cyclomatic Complexity 5 fs/dcache.c:dentry_lock_for_move Cyclomatic Complexity 8 fs/dcache.c:__d_move Cyclomatic Complexity 1 fs/dcache.c:d_move Cyclomatic Complexity 5 fs/dcache.c:d_exchange Cyclomatic Complexity 6 fs/dcache.c:__d_unalias Cyclomatic Complexity 13 fs/dcache.c:d_splice_alias Cyclomatic Complexity 7 fs/dcache.c:d_add_ci Cyclomatic Complexity 3 fs/dcache.c:__d_path Cyclomatic Complexity 3 fs/dcache.c:d_absolute_path Cyclomatic Complexity 6 fs/dcache.c:d_path Cyclomatic Complexity 2 fs/dcache.c:dynamic_dname Cyclomatic Complexity 4 fs/dcache.c:simple_dname Cyclomatic Complexity 1 fs/dcache.c:dentry_path_raw Cyclomatic Complexity 5 fs/dcache.c:dentry_path Cyclomatic Complexity 1 fs/dcache.c:SyS_getcwd Cyclomatic Complexity 4 fs/dcache.c:is_subdir Cyclomatic Complexity 1 fs/dcache.c:d_genocide Cyclomatic Complexity 4 fs/dcache.c:d_tmpfile In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from include/uapi/linux/posix_types.h:4, from include/uapi/linux/types.h:13, from include/linux/types.h:5, from include/linux/syscalls.h:70, from fs/dcache.c:17: fs/dcache.c: In function 'd_add': >> include/linux/compiler.h:323:14: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized] { .__val = (__force typeof(x)) (val) }; \ ^ fs/dcache.c:2520:11: note: 'n' was declared here unsigned n; ^ In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from include/uapi/linux/posix_types.h:4, from include/uapi/linux/types.h:13, from include/linux/types.h:5, from include/linux/syscalls.h:70, from fs/dcache.c:17: fs/dcache.c: In function 'd_splice_alias': >> include/linux/compiler.h:323:14: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized] { .__val = (__force typeof(x)) (val) }; \ ^ fs/dcache.c:2520:11: note: 'n' was declared here unsigned n; ^ vim +/n +323 include/linux/compiler.h d976441f Andrey Ryabinin 2015-10-19 307 __read_once_size(&(x), __u.__c, sizeof(x)); \ d976441f Andrey Ryabinin 2015-10-19 308 else \ d976441f Andrey Ryabinin 2015-10-19 309 __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ d976441f Andrey Ryabinin 2015-10-19 310 __u.__val; \ d976441f Andrey Ryabinin 2015-10-19 311 }) d976441f Andrey Ryabinin 2015-10-19 312 #define READ_ONCE(x) __READ_ONCE(x, 1) d976441f Andrey Ryabinin 2015-10-19 313 d976441f Andrey Ryabinin 2015-10-19 314 /* d976441f Andrey Ryabinin 2015-10-19 315 * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need d976441f Andrey Ryabinin 2015-10-19 316 * to hide memory access from KASAN. d976441f Andrey Ryabinin 2015-10-19 317 */ d976441f Andrey Ryabinin 2015-10-19 318 #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) 230fa253 Christian Borntraeger 2014-11-25 319 43239cbe Christian Borntraeger 2015-01-13 320 #define WRITE_ONCE(x, val) \ ba33034f Christian Borntraeger 2015-08-04 321 ({ \ ba33034f Christian Borntraeger 2015-08-04 322 union { typeof(x) __val; char __c[1]; } __u = \ ba33034f Christian Borntraeger 2015-08-04 @323 { .__val = (__force typeof(x)) (val) }; \ ba33034f Christian Borntraeger 2015-08-04 324 __write_once_size(&(x), __u.__c, sizeof(x)); \ ba33034f Christian Borntraeger 2015-08-04 325 __u.__val; \ ba33034f Christian Borntraeger 2015-08-04 326 }) 230fa253 Christian Borntraeger 2014-11-25 327 ^1da177e Linus Torvalds 2005-04-16 328 #endif /* __KERNEL__ */ ^1da177e Linus Torvalds 2005-04-16 329 ^1da177e Linus Torvalds 2005-04-16 330 #endif /* __ASSEMBLY__ */ ^1da177e Linus Torvalds 2005-04-16 331 :::::: The code at line 323 was first introduced by commit :::::: ba33034fffc1189d95301bd865f1c799256e72a2 locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic :::::: TO: Christian Borntraeger <borntraeger@xxxxxxxxxx> :::::: CC: Ingo Molnar <mingo@xxxxxxxxxx> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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