tree: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-5.9.y-rt-rebase head: 2e71df3c0898b1305428692e75f456de3bbb9140 commit: 3adf3b1805eb97b3ee7a49af496cfa7e44c8a90d [135/216] rtmutex: add ww_mutex addon for mutex-rt config: mips-randconfig-r025-20200921 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 4e8c028158b56d9c2142a62464e8e0686bde3584) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu git checkout 3adf3b1805eb97b3ee7a49af496cfa7e44c8a90d # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): kernel/locking/rtmutex.c:69:20: warning: unused function 'clear_rt_mutex_waiters' static inline void clear_rt_mutex_waiters(struct rt_mutex ^ static __always_inline void ww_mutex_lock_acquired(struct ww_mutex ^ ww_mutex_deadlock_injection(struct ww_mutex struct ww_acquire_ctx ^ fatal error: error in backend: Nested variants found in inline asm string: ' .set push .set mips64r2 .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/atomic.h", .line = 153, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif 1: ll $1, $2 # atomic_fetch_add addu $0, $1, $3 sc $0, $2 beqz $0, 1b .set pop move $0, $1 ' clang-12: error: clang frontend command failed with exit code 70 (use -v to see invocation) clang version 12.0.0 (git://gitmirror/llvm_project 4e8c028158b56d9c2142a62464e8e0686bde3584) Target: mips-unknown-linux-gnu Thread model: posix InstalledDir: /opt/cross/clang-4e8c028158/bin clang-12: note: diagnostic msg: Makefile arch include kernel scripts source usr # https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/com... git remote add linux-rt-devel https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git git fetch --no-tags linux-rt-devel linux-5.9.y-rt-rebase git checkout 3adf3b1805eb97b3ee7a49af496cfa7e44c8a90d vim +/ww_mutex_lock_acquired +1617 kernel/locking/rtmutex.c 1616 1618 struct ww_acquire_ctx *ww_ctx) 1619 { 1620 #ifdef CONFIG_DEBUG_MUTEXES 1621 /* 1622 * If this WARN_ON triggers, you used ww_mutex_lock to acquire, 1623 * but released with a normal mutex_unlock in this call. 1624 * 1625 * This should never happen, always use ww_mutex_unlock. 1626 */ 1627 DEBUG_LOCKS_WARN_ON(ww->ctx); 1628 1629 /* 1630 * Not quite done after calling ww_acquire_done() ? 1631 */ 1632 DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire); 1633 1634 if (ww_ctx->contending_lock) { 1635 /* 1636 * After -EDEADLK you tried to 1637 * acquire a different ww_mutex? Bad! 1638 */ 1639 DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww); 1640 1641 /* 1642 * You called ww_mutex_lock after receiving -EDEADLK, 1643 * but 'forgot' to unlock everything else first? 1644 */ 1645 DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0); 1646 ww_ctx->contending_lock = NULL; 1647 } 1648 1649 /* 1650 * Naughty, using a different class will lead to undefined behavior! 1651 */ 1652 DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class); 1653 #endif 1654 ww_ctx->acquired++; 1655 } 1656 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org