Date: Tue, 25 Nov 2025 17:32:32 +0100 From: FreeBSD User <freebsd@walstatt-de.de> To: dev-commits-src-main@freebsd.org Subject: Re: git: 9562994a7aac - main - kernel linker: Disable local sym resolution by default Message-ID: <20251125173232.7da258c1@hermann> In-Reply-To: <6925b3f4.2c48c.61345a6b@gitrepo.freebsd.org> References: <6925b3f4.2c48c.61345a6b@gitrepo.freebsd.org>
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On Tue, 25 Nov 2025 13:49:40 +0000 Ed Maste <emaste@FreeBSD.org> wrote: > The branch main has been updated by emaste: > > URL: https://cgit.FreeBSD.org/src/commit/?id=9562994a7aacee2baae6ddee1a7b558b48ae39ef > > commit 9562994a7aacee2baae6ddee1a7b558b48ae39ef > Author: Ed Maste <emaste@FreeBSD.org> > AuthorDate: 2024-11-25 19:05:54 +0000 > Commit: Ed Maste <emaste@FreeBSD.org> > CommitDate: 2025-11-25 13:49:20 +0000 > > kernel linker: Disable local sym resolution by default > > In 95c20faf11a1 and ecd8245e0d77 kib introduced support to have the > kernel linker stop resolving local symbols from other files, but did > not enable it by default to avoid surprises. Flip the default now, > before FreeBSD 16.0. > > The debug.link_elf_leak_locals and debug.link_elf_obj_leak_locals > sysctls are available to revert to the previous behaviour if necessary. > > PR: 207898 > Reviewed by: bz > Relnotes: Yes > Sponsored by: The FreeBSD Foundation > Differential Revision: https://reviews.freebsd.org/D47742 > --- > UPDATING | 9 +++++++++ > sys/kern/link_elf.c | 2 +- > sys/kern/link_elf_obj.c | 2 +- > 3 files changed, 11 insertions(+), 2 deletions(-) > > diff --git a/UPDATING b/UPDATING > index aaef0e5b4cd3..7f0cb44181d3 100644 > --- a/UPDATING > +++ b/UPDATING > @@ -27,6 +27,15 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 16.x IS SLOW: > world, or to merely disable the most expensive debugging functionality > at runtime, run "ln -s 'abort:false,junk:false' /etc/malloc.conf".) > > +20251125: > + The `debug.link_elf_leak_locals` and `debug.link_elf_obj_leak_locals` > + sysctls now default to 0, so the kernel module linker no longer > + performs symbol resolution against local symbols from other modules. > + > + If a kernel module now fails to load because of an unresolved symbol, > + set these sysctls to 1 and file a bug report including details about > + the affected module. > + > 20251115: > The FreeBSD-base repository is now defined in /etc/pkg/FreeBSD.conf, > disabled by default. In -CURRENT and -STABLE this points at nightly > diff --git a/sys/kern/link_elf.c b/sys/kern/link_elf.c > index ebd203858b66..f910fc3d5df5 100644 > --- a/sys/kern/link_elf.c > +++ b/sys/kern/link_elf.c > @@ -203,7 +203,7 @@ static struct linker_class link_elf_class = { > link_elf_methods, sizeof(struct elf_file) > }; > > -static bool link_elf_leak_locals = true; > +static bool link_elf_leak_locals = false; > SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals, > CTLFLAG_RWTUN, &link_elf_leak_locals, 0, > "Allow local symbols to participate in global module symbol resolution"); > diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c > index a3a53a39bfd6..759cd75cba31 100644 > --- a/sys/kern/link_elf_obj.c > +++ b/sys/kern/link_elf_obj.c > @@ -192,7 +192,7 @@ static struct linker_class link_elf_class = { > link_elf_methods, sizeof(struct elf_file) > }; > > -static bool link_elf_obj_leak_locals = true; > +static bool link_elf_obj_leak_locals = false; > SYSCTL_BOOL(_debug, OID_AUTO, link_elf_obj_leak_locals, > CTLFLAG_RWTUN, &link_elf_obj_leak_locals, 0, > "Allow local symbols to participate in global module symbol resolution"); > After updating recent CURRENT, x11/nvidia-driver (nvidia-modeset) fails to load. Setting both debug.link_elf_leak_locals=1 debug.link_elf_obj_leak_locals=1 in /etc/sysctl.conf results in a stuck system: No graphics, stuck keyboard (no change to console possible). Shutting down the box leaves me with a stuck system (need to shutoff power the hard way, no reboot). Regards, oliverhelp
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