Date: Tue, 20 Jul 2021 11:40:59 GMT From: Dmitry Chagin <dchagin@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: cf8d74e3fe63 - main - linux(4): Allow musl brand to use FUTEX_REQUEUE op. Message-ID: <202107201140.16KBexRo089960@gitrepo.freebsd.org>
next in thread | raw e-mail | index | archive | help
The branch main has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=cf8d74e3fe63da7359d6ca7e0b4b57c5684c2845 commit cf8d74e3fe63da7359d6ca7e0b4b57c5684c2845 Author: Dmitry Chagin <dchagin@FreeBSD.org> AuthorDate: 2021-07-20 11:39:20 +0000 Commit: Dmitry Chagin <dchagin@FreeBSD.org> CommitDate: 2021-07-20 11:39:20 +0000 linux(4): Allow musl brand to use FUTEX_REQUEUE op. Initial patch from submitter was adapted by me to prevent unconditional FUTEX_REQUEUE use. PR: 255947 Submitted by: Philippe Michaud-Boudreault Differential Revision: https://reviews.freebsd.org/D30332 --- sys/amd64/linux/linux_sysvec.c | 3 ++- sys/amd64/linux32/linux32_sysvec.c | 3 ++- sys/compat/linux/linux.h | 5 ++++ sys/compat/linux/linux_futex.c | 49 +++++++++++++++++++++++++------------- sys/i386/linux/linux_sysvec.c | 3 ++- 5 files changed, 43 insertions(+), 20 deletions(-) diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c index dc9a77093bcd..fede294ce706 100644 --- a/sys/amd64/linux/linux_sysvec.c +++ b/sys/amd64/linux/linux_sysvec.c @@ -991,7 +991,8 @@ static Elf64_Brandinfo linux_muslbrand = { .sysvec = &elf_linux_sysvec, .interp_newpath = NULL, .brand_note = &linux64_brandnote, - .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE + .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE | + LINUX_BI_FUTEX_REQUEUE }; Elf64_Brandinfo *linux_brandlist[] = { diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c index 5176029605bf..901c79fcdda8 100644 --- a/sys/amd64/linux32/linux32_sysvec.c +++ b/sys/amd64/linux32/linux32_sysvec.c @@ -1154,7 +1154,8 @@ static Elf32_Brandinfo linux_muslbrand = { .sysvec = &elf_linux_sysvec, .interp_newpath = NULL, .brand_note = &linux32_brandnote, - .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE + .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE | + LINUX_BI_FUTEX_REQUEUE }; Elf32_Brandinfo *linux_brandlist[] = { diff --git a/sys/compat/linux/linux.h b/sys/compat/linux/linux.h index 15830b5b387e..730aece66a6a 100644 --- a/sys/compat/linux/linux.h +++ b/sys/compat/linux/linux.h @@ -30,6 +30,11 @@ #include <sys/queue.h> +/* + * Private Brandinfo flags + */ +#define LINUX_BI_FUTEX_REQUEUE 0x01000000 + /* * poll() */ diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c index 1ba11ed3fc57..2ee18c26cf24 100644 --- a/sys/compat/linux/linux_futex.c +++ b/sys/compat/linux/linux_futex.c @@ -46,6 +46,7 @@ __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $") #include <sys/param.h> #include <sys/systm.h> #include <sys/imgact.h> +#include <sys/imgact_elf.h> #include <sys/kernel.h> #include <sys/ktr.h> #include <sys/lock.h> @@ -234,6 +235,7 @@ struct linux_futex_args { struct timespec *ts; uint32_t *uaddr2; uint32_t val3; + bool val3_compare; struct timespec kts; }; @@ -648,6 +650,7 @@ static int linux_futex(struct thread *td, struct linux_futex_args *args) { struct linux_pemuldata *pem; + struct proc *p; if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { args->flags = 0; @@ -695,6 +698,33 @@ linux_futex(struct thread *td, struct linux_futex_args *args) return (linux_futex_wake(td, args)); + case LINUX_FUTEX_REQUEUE: + /* + * Glibc does not use this operation since version 2.3.3, + * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. + * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when + * FUTEX_REQUEUE returned EINVAL. + */ + pem = pem_find(td->td_proc); + if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { + linux_msg(td, "unsupported FUTEX_REQUEUE"); + pem->flags |= LINUX_XDEPR_REQUEUEOP; + LIN_SDT_PROBE0(futex, linux_futex, + deprecated_requeue); + } + + /* + * The above is true, however musl libc does make use of the + * futex requeue operation, allow operation for brands which + * set LINUX_BI_FUTEX_REQUEUE bit of Brandinfo flags. + */ + p = td->td_proc; + Elf_Brandinfo *bi = p->p_elf_brandinfo; + if (bi == NULL || ((bi->flags & LINUX_BI_FUTEX_REQUEUE)) == 0) + return (EINVAL); + args->val3_compare = false; + /* FALLTHROUGH */ + case LINUX_FUTEX_CMP_REQUEUE: LIN_SDT_PROBE5(futex, linux_futex, debug_cmp_requeue, args->uaddr, args->val, args->val3, args->uaddr2, @@ -749,22 +779,6 @@ linux_futex(struct thread *td, struct linux_futex_args *args) } return (ENOSYS); - case LINUX_FUTEX_REQUEUE: - /* - * Glibc does not use this operation since version 2.3.3, - * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. - * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when - * FUTEX_REQUEUE returned EINVAL. - */ - pem = pem_find(td->td_proc); - if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { - linux_msg(td, "unsupported FUTEX_REQUEUE"); - pem->flags |= LINUX_XDEPR_REQUEUEOP; - LIN_SDT_PROBE0(futex, linux_futex, - deprecated_requeue); - } - return (EINVAL); - case LINUX_FUTEX_WAIT_REQUEUE_PI: /* not yet implemented */ pem = pem_find(td->td_proc); @@ -921,7 +935,7 @@ retry: error); return (error); } - if (val != args->val3) { + if (args->val3_compare == true && val != args->val3) { LIN_SDT_PROBE2(futex, linux_futex, debug_cmp_requeue_value_neq, args->val, val); LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", @@ -1016,6 +1030,7 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) .ts = NULL, .uaddr2 = args->uaddr2, .val3 = args->val3, + .val3_compare = true, }; struct l_timespec lts; int error; diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c index f3101db96d41..1fcc1b6eb5a0 100644 --- a/sys/i386/linux/linux_sysvec.c +++ b/sys/i386/linux/linux_sysvec.c @@ -1099,7 +1099,8 @@ static Elf32_Brandinfo linux_muslbrand = { .sysvec = &elf_linux_sysvec, .interp_newpath = NULL, .brand_note = &linux_brandnote, - .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE + .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE | + LINUX_BI_FUTEX_REQUEUE }; Elf32_Brandinfo *linux_brandlist[] = {
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202107201140.16KBexRo089960>