Date: Wed, 1 Jul 2020 15:27:34 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r362838 - stable/12/sys/kern Message-ID: <202007011527.061FRY2u090347@repo.freebsd.org>
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Author: markj Date: Wed Jul 1 15:27:34 2020 New Revision: 362838 URL: https://svnweb.freebsd.org/changeset/base/362838 Log: MFC r362789 (by gallatin): Fix a panic when unloading firmware Modified: stable/12/sys/kern/subr_firmware.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/kern/subr_firmware.c ============================================================================== --- stable/12/sys/kern/subr_firmware.c Wed Jul 1 15:17:45 2020 (r362837) +++ stable/12/sys/kern/subr_firmware.c Wed Jul 1 15:27:34 2020 (r362838) @@ -394,14 +394,12 @@ EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NUL static void unloadentry(void *unused1, int unused2) { - struct priv_fw *fp, *tmp; + struct priv_fw *fp; int err; - bool changed; mtx_lock(&firmware_mtx); - changed = false; restart: - LIST_FOREACH_SAFE(fp, &firmware_table, link, tmp) { + LIST_FOREACH(fp, &firmware_table, link) { if (fp->file == NULL || fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) continue; @@ -412,7 +410,6 @@ restart: * 2. clear FW_UNLOAD so we don't try this entry again. * 3. release the lock while trying to unload the module. */ - changed = true; fp->flags &= ~FW_UNLOAD; /* do not try again */ /* @@ -422,9 +419,11 @@ restart: mtx_unlock(&firmware_mtx); err = linker_release_module(NULL, NULL, fp->file); mtx_lock(&firmware_mtx); - } - if (changed) { - changed = false; + + /* + * When we dropped the lock, another thread could have + * removed an element, so we must restart the scan. + */ goto restart; } mtx_unlock(&firmware_mtx);
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