git: f08247fd888e - main - Assert that mbufs are writable if we write to them

[Kristof Provost]

The branch main has been updated by kp:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=f08247fd888e6f7db0ecf2aaa39377144ac40b4c

commit f08247fd888e6f7db0ecf2aaa39377144ac40b4c
Author:     Kristof Provost <k...@freebsd.org>
AuthorDate: 2024-09-10 20:15:31 +0000
Commit:     Kristof Provost <k...@freebsd.org>
CommitDate: 2024-09-11 11:17:48 +0000

    Assert that mbufs are writable if we write to them
    
    m_copyback() modifies the mbuf, so it must be a writable mbuf.
    
    Reviewed by:    glebius
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
    Differential Revision:  https://reviews.freebsd.org/D46627
---
 sys/kern/uipc_mbuf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index f6ce9b5cc74b..3232af880925 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1280,6 +1280,8 @@ m_copyback(struct mbuf *m0, int off, int len, c_caddr_t 
cp)
 
        if (m0 == NULL)
                return;
+
+       MPASS(M_WRITABLE(m0));
        while (off > (mlen = m->m_len)) {
                off -= mlen;
                totlen += mlen;