Author: sbruno Date: Thu Jun 18 02:04:20 2015 New Revision: 284535 URL: https://svnweb.freebsd.org/changeset/base/284535
Log: This change replaces the mutex with a sx lock for the interpreter list to avoid the problem of holding a non-sleep lock during a page fault as reported by witness. It also uses atomics where possible to avoid having to acquire the exclusive lock. In addition, it consistently uses memset()/memcpy() instead of bzero()/bcopy(). Differential Revision: https://reviews.freebsd.org/D1971 Submitted by: sson Reviewed by: jhb Modified: head/sys/kern/imgact_binmisc.c Modified: head/sys/kern/imgact_binmisc.c ============================================================================== --- head/sys/kern/imgact_binmisc.c Thu Jun 18 00:57:52 2015 (r284534) +++ head/sys/kern/imgact_binmisc.c Thu Jun 18 02:04:20 2015 (r284535) @@ -1,5 +1,5 @@ /*- - * Copyright (c) 2013, Stacey D. Son + * Copyright (c) 2013-15, Stacey D. Son * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -41,6 +41,9 @@ __FBSDID("$FreeBSD$"); #include <sys/malloc.h> #include <sys/mutex.h> #include <sys/sysctl.h> +#include <sys/sx.h> + +#include <machine/atomic.h> /** * Miscellaneous binary interpreter image activator. @@ -96,7 +99,7 @@ static SLIST_HEAD(, imgact_binmisc_entry static int interp_list_entry_count = 0; -static struct mtx interp_list_mtx; +static struct sx interp_list_sx; int imgact_binmisc_exec(struct image_params *imgp); @@ -111,7 +114,7 @@ imgact_binmisc_populate_interp(char *str char t[IBE_INTERP_LEN_MAX]; char *sp, *tp; - bzero(t, sizeof(t)); + memset(t, 0, sizeof(t)); /* * Normalize interpreter string. Replace white space between args with @@ -152,8 +155,6 @@ imgact_binmisc_new_entry(ximgact_binmisc imgact_binmisc_entry_t *ibe = NULL; size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX); - mtx_assert(&interp_list_mtx, MA_NOTOWNED); - ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO); ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO); @@ -203,7 +204,7 @@ imgact_binmisc_find_entry(char *name) { imgact_binmisc_entry_t *ibe; - mtx_assert(&interp_list_mtx, MA_OWNED); + sx_assert(&interp_list_sx, SA_LOCKED); SLIST_FOREACH(ibe, &interpreter_list, link) { if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0) @@ -260,21 +261,20 @@ imgact_binmisc_add_entry(ximgact_binmisc } } - mtx_lock(&interp_list_mtx); + sx_xlock(&interp_list_sx); if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) { - mtx_unlock(&interp_list_mtx); + sx_xunlock(&interp_list_sx); return (EEXIST); } - mtx_unlock(&interp_list_mtx); + /* Preallocate a new entry. */ ibe = imgact_binmisc_new_entry(xbe); if (!ibe) return (ENOMEM); - mtx_lock(&interp_list_mtx); SLIST_INSERT_HEAD(&interpreter_list, ibe, link); interp_list_entry_count++; - mtx_unlock(&interp_list_mtx); + sx_xunlock(&interp_list_sx); return (0); } @@ -288,14 +288,14 @@ imgact_binmisc_remove_entry(char *name) { imgact_binmisc_entry_t *ibe; - mtx_lock(&interp_list_mtx); + sx_xlock(&interp_list_sx); if ((ibe = imgact_binmisc_find_entry(name)) == NULL) { - mtx_unlock(&interp_list_mtx); + sx_xunlock(&interp_list_sx); return (ENOENT); } SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link); interp_list_entry_count--; - mtx_unlock(&interp_list_mtx); + sx_xunlock(&interp_list_sx); imgact_binmisc_destroy_entry(ibe); @@ -311,14 +311,14 @@ imgact_binmisc_disable_entry(char *name) { imgact_binmisc_entry_t *ibe; - mtx_lock(&interp_list_mtx); + sx_slock(&interp_list_sx); if ((ibe = imgact_binmisc_find_entry(name)) == NULL) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (ENOENT); } ibe->ibe_flags &= ~IBF_ENABLED; - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (0); } @@ -332,14 +332,14 @@ imgact_binmisc_enable_entry(char *name) { imgact_binmisc_entry_t *ibe; - mtx_lock(&interp_list_mtx); + sx_slock(&interp_list_sx); if ((ibe = imgact_binmisc_find_entry(name)) == NULL) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (ENOENT); } - ibe->ibe_flags |= IBF_ENABLED; - mtx_unlock(&interp_list_mtx); + atomic_set_32(&ibe->ibe_flags, IBF_ENABLED); + sx_sunlock(&interp_list_sx); return (0); } @@ -350,9 +350,9 @@ imgact_binmisc_populate_xbe(ximgact_binm { uint32_t i; - mtx_assert(&interp_list_mtx, MA_OWNED); + sx_assert(&interp_list_sx, SA_LOCKED); - bzero(xbe, sizeof(*xbe)); + memset(xbe, 0, sizeof(*xbe)); strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX); /* Copy interpreter string. Replace NULL breaks with space. */ @@ -382,14 +382,14 @@ imgact_binmisc_lookup_entry(char *name, imgact_binmisc_entry_t *ibe; int error = 0; - mtx_lock(&interp_list_mtx); + sx_slock(&interp_list_sx); if ((ibe = imgact_binmisc_find_entry(name)) == NULL) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (ENOENT); } error = imgact_binmisc_populate_xbe(xbe, ibe); - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (error); } @@ -404,12 +404,12 @@ imgact_binmisc_get_all_entries(struct sy imgact_binmisc_entry_t *ibe; int error = 0, count; - mtx_lock(&interp_list_mtx); + sx_slock(&interp_list_sx); count = interp_list_entry_count; /* Don't block in malloc() while holding lock. */ xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_NOWAIT|M_ZERO); if (!xbe) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (ENOMEM); } @@ -419,7 +419,7 @@ imgact_binmisc_get_all_entries(struct sy if (error) break; } - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); if (!error) error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count); @@ -556,7 +556,7 @@ imgact_binmisc_find_interpreter(const ch int i; size_t sz; - mtx_assert(&interp_list_mtx, MA_OWNED); + sx_assert(&interp_list_sx, SA_LOCKED); SLIST_FOREACH(ibe, &interpreter_list, link) { if (!(IBF_ENABLED & ibe->ibe_flags)) @@ -593,15 +593,15 @@ imgact_binmisc_exec(struct image_params char *s, *d; /* Do we have an interpreter for the given image header? */ - mtx_lock(&interp_list_mtx); + sx_slock(&interp_list_sx); if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (-1); } /* No interpreter nesting allowed. */ if (imgp->interpreted & IMGACT_BINMISC) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); return (ENOEXEC); } @@ -649,7 +649,7 @@ imgact_binmisc_exec(struct image_params default: /* Hmm... This shouldn't happen. */ - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); printf("%s: Unknown macro #%c sequence in " "interpreter string\n", KMOD_NAME, *(s + 1)); error = EINVAL; @@ -660,7 +660,7 @@ imgact_binmisc_exec(struct image_params /* Check to make sure we won't overrun the stringspace. */ if (offset > imgp->args->stringspace) { - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); error = E2BIG; goto done; } @@ -720,7 +720,7 @@ imgact_binmisc_exec(struct image_params s++; } *d = '\0'; - mtx_unlock(&interp_list_mtx); + sx_sunlock(&interp_list_sx); if (!error) imgp->interpreter_name = imgp->args->begin_argv; @@ -736,7 +736,7 @@ static void imgact_binmisc_init(void *arg) { - mtx_init(&interp_list_mtx, KMOD_NAME, NULL, MTX_DEF); + sx_init(&interp_list_sx, KMOD_NAME); } static void @@ -745,15 +745,15 @@ imgact_binmisc_fini(void *arg) imgact_binmisc_entry_t *ibe, *ibe_tmp; /* Free all the interpreters. */ - mtx_lock(&interp_list_mtx); + sx_xlock(&interp_list_sx); SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) { SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link); imgact_binmisc_destroy_entry(ibe); } - mtx_unlock(&interp_list_mtx); + sx_xunlock(&interp_list_sx); - mtx_destroy(&interp_list_mtx); + sx_destroy(&interp_list_sx); } SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init, 0); _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
