Date: Thu, 7 Feb 2019 06:55:26 +0000 (UTC) From: Dimitry Andric <dim@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r343863 - in stable: 11/sys/i386/i386 12/sys/i386/i386 Message-ID: <201902070655.x176tQR3019865@repo.freebsd.org>
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Author: dim Date: Thu Feb 7 06:55:26 2019 New Revision: 343863 URL: https://svnweb.freebsd.org/changeset/base/343863 Log: MFC r343748: Use NLDT to get number of LDTs on i386 Compiling a GENERIC kernel for i386 with clang 8.0 results in the following warning: /usr/src/sys/i386/i386/sys_machdep.c:542:40: error: 'sizeof ((ldt))' will return the size of the pointer, not the array itself [-Werror,-Wsizeof-pointer-div] nldt = pldt != NULL ? pldt->ldt_len : nitems(ldt); ^~~~~~~~~~~ /usr/src/sys/sys/param.h:299:32: note: expanded from macro 'nitems' #define nitems(x) (sizeof((x)) / sizeof((x)[0])) ~~~~~~~~~~~ ^ Indeed, 'ldt' is declared as 'union descriptor *', so nitems() is not the right way to determine the number of LDTs. Instead, the NLDT define from sys/x86/include/segments.h should be used. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D19074 Modified: stable/11/sys/i386/i386/sys_machdep.c Directory Properties: stable/11/ (props changed) Changes in other areas also in this revision: Modified: stable/12/sys/i386/i386/sys_machdep.c Directory Properties: stable/12/ (props changed) Modified: stable/11/sys/i386/i386/sys_machdep.c ============================================================================== --- stable/11/sys/i386/i386/sys_machdep.c Thu Feb 7 05:40:51 2019 (r343862) +++ stable/11/sys/i386/i386/sys_machdep.c Thu Feb 7 06:55:26 2019 (r343863) @@ -538,7 +538,7 @@ i386_get_ldt(struct thread *td, struct i386_ldt_args * data = malloc(num * sizeof(union descriptor), M_TEMP, M_WAITOK); mtx_lock_spin(&dt_lock); pldt = td->td_proc->p_md.md_ldt; - nldt = pldt != NULL ? pldt->ldt_len : nitems(ldt); + nldt = pldt != NULL ? pldt->ldt_len : NLDT; if (uap->start >= nldt) { num = 0; } else {
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