Date: Mon, 01 Dec 2025 14:21:02 +0000 From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 72b114169bd5 - main - linker: Avoid invoking eventhandlers on incompletely loaded files Message-ID: <692da44e.2ab04.29ad736b@gitrepo.freebsd.org>
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The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=72b114169bd56ec157d746a2df87b3a4617065b3 commit 72b114169bd56ec157d746a2df87b3a4617065b3 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2025-11-26 18:15:48 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2025-12-01 14:19:18 +0000 linker: Avoid invoking eventhandlers on incompletely loaded files We do not invoke the kld_load eventhandler until after the file is fully linked, so don't invoke the kld_unload_try or kld_unload event handlers unless the file is fully linked either. In my case, the dtrace SDT kld_unload_try handler was running before relocations were processed against the file, and that caused problems when sdt_kld_unload_probes() accesses elements of a linker set. Move the kld_unload handler invocation earlier, to after sysuninits have been run. This is a bit more consistent with the kld_load handler. PR: 291238 Reviewed by: imp, emaste, kib MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D53938 --- sys/kern/kern_linker.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c index e2f63cbc0c5a..9559b5233a3e 100644 --- a/sys/kern/kern_linker.c +++ b/sys/kern/kern_linker.c @@ -703,9 +703,11 @@ linker_file_unload(linker_file_t file, int flags) /* Give eventhandlers a chance to prevent the unload. */ error = 0; - EVENTHANDLER_INVOKE(kld_unload_try, file, &error); - if (error != 0) - return (EBUSY); + if ((file->flags & LINKER_FILE_LINKED) != 0) { + EVENTHANDLER_INVOKE(kld_unload_try, file, &error); + if (error != 0) + return (EBUSY); + } KLD_DPF(FILE, ("linker_file_unload: file is unloading," " informing modules\n")); @@ -768,10 +770,12 @@ linker_file_unload(linker_file_t file, int flags) * Don't try to run SYSUNINITs if we are unloaded due to a * link error. */ - if (file->flags & LINKER_FILE_LINKED) { + if ((file->flags & LINKER_FILE_LINKED) != 0) { file->flags &= ~LINKER_FILE_LINKED; linker_file_unregister_sysctls(file); linker_file_sysuninit(file); + EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address, + file->size); } TAILQ_REMOVE(&linker_files, file, link); @@ -788,9 +792,6 @@ linker_file_unload(linker_file_t file, int flags) LINKER_UNLOAD(file); - EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address, - file->size); - if (file->filename) { free(file->filename, M_LINKER); file->filename = NULL;help
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