Date: Wed, 25 Feb 2026 11:30:37 +0000 From: Bojan Novk=?utf-8?Q?ovi=C4=87?= <bnovkov@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: bce0c14fe19d - main - mpool/mpool_get.c: Avoid clobbering 'errno' when handling 'pread' errors Message-ID: <699edd5d.3abb8.3b1aebcd@gitrepo.freebsd.org>
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The branch main has been updated by bnovkov: URL: https://cgit.FreeBSD.org/src/commit/?id=bce0c14fe19defeef4f02cfebc018e9adf979783 commit bce0c14fe19defeef4f02cfebc018e9adf979783 Author: Bojan Novković <bnovkov@FreeBSD.org> AuthorDate: 2026-02-23 15:30:26 +0000 Commit: Bojan Novković <bnovkov@FreeBSD.org> CommitDate: 2026-02-25 11:30:05 +0000 mpool/mpool_get.c: Avoid clobbering 'errno' when handling 'pread' errors POSIX.1-2024 states that the 'free' function "shall not modify errno if ptr is a null pointer or a pointer previously returned as if by malloc() and not yet deallocated". However this is a fairly recent addition and non-compliant allocators might still clobber 'errno', causing 'mpool_get' to return the wrong error code. Fix this by saving and restoring 'errno' after calling 'free'. Sponsored by: Klara, Inc. Reviewed by: obiwac Differential Revision: https://reviews.freebsd.org/D55463 MFC after: 1 week --- lib/libc/db/mpool/mpool.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/libc/db/mpool/mpool.c b/lib/libc/db/mpool/mpool.c index 1bab66d73baf..0df19dc09e4d 100644 --- a/lib/libc/db/mpool/mpool.c +++ b/lib/libc/db/mpool/mpool.c @@ -214,10 +214,14 @@ mpool_get(MPOOL *mp, pgno_t pgno, /* Read in the contents. */ off = mp->pagesize * pgno; if ((nr = pread(mp->fd, bp->page, mp->pagesize, off)) != (ssize_t)mp->pagesize) { + int serrno; + switch (nr) { case -1: /* errno is set for us by pread(). */ + serrno = errno; free(bp); + errno = serrno; mp->curcache--; return (NULL); case 0:home | help
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