Date: Wed, 1 Feb 2023 23:41:38 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 25c862ae503a - main - libthr pshared: correct a bug in allocation Message-ID: <202302012341.311NfcIQ089003@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=25c862ae503a1c99458f4e055fd50c878fadbea3 commit 25c862ae503a1c99458f4e055fd50c878fadbea3 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2023-02-01 20:12:45 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2023-02-01 22:59:27 +0000 libthr pshared: correct a bug in allocation When __thr_pshared_offpage() is called for allocation, it must not use the cached offpage for the key. Instead, the cached offpage must be unmapped and removed from the cache, if any. It is legitimate for the user code to unmap the shared lock object without destroying it, and then mapping something over the freed VA to carry another shared lock. In this case the cached offpage must be un-cached. PR: 269277 Reported by: rau8344@gmail.com Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D38345 --- lib/libthr/thread/thr_pshared.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/lib/libthr/thread/thr_pshared.c b/lib/libthr/thread/thr_pshared.c index 37b44ab73582..446e9983bcae 100644 --- a/lib/libthr/thread/thr_pshared.c +++ b/lib/libthr/thread/thr_pshared.c @@ -232,11 +232,16 @@ __thr_pshared_offpage(void *key, int doalloc) int fd, ins_done; curthread = _get_curthread(); - pshared_rlock(curthread); - res = pshared_lookup(key); - pshared_unlock(curthread); - if (res != NULL) - return (res); + if (doalloc) { + pshared_destroy(curthread, key); + res = NULL; + } else { + pshared_rlock(curthread); + res = pshared_lookup(key); + pshared_unlock(curthread); + if (res != NULL) + return (res); + } fd = _umtx_op(NULL, UMTX_OP_SHM, doalloc ? UMTX_SHM_CREAT : UMTX_SHM_LOOKUP, key, NULL); if (fd == -1)
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