Date: Tue, 12 Nov 2024 10:23:57 -0500 From: John Baldwin <jhb@FreeBSD.org> To: Jose Luis Duran <jlduran@FreeBSD.org>, src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: 1fa6daaafd74 - main - ipfilter: Avoid stopping with a lock held Message-ID: <09923ad3-4065-4a31-b35f-74f84e09cff1@FreeBSD.org> In-Reply-To: <202411120347.4AC3lPOA015167@gitrepo.freebsd.org> References: <202411120347.4AC3lPOA015167@gitrepo.freebsd.org>
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On 11/11/24 19:47, Jose Luis Duran wrote: > The branch main has been updated by jlduran: > > URL: https://cgit.FreeBSD.org/src/commit/?id=1fa6daaafd74c1a457dcfe26e0a5943b5441dc9d > > commit 1fa6daaafd74c1a457dcfe26e0a5943b5441dc9d > Author: Jose Luis Duran <jlduran@FreeBSD.org> > AuthorDate: 2024-11-02 17:58:59 +0000 > Commit: Jose Luis Duran <jlduran@FreeBSD.org> > CommitDate: 2024-11-12 03:46:15 +0000 > > ipfilter: Avoid stopping with a lock held > > Avoid calling _callout_stop_safe with a non-sleepable lock held when > detaching by initializing callout_init_rw() with CALLOUT_SHAREDLOCK. > > It avoids the following WITNESS warning when stopping the service: > > # service ipfilter stop > calling _callout_stop_safe with the following non-sleepable locks held: > shared rw ipf filter load/unload mutex (ipf filter load/unload mutex) r = 0 (0xffff0000417c7530) locked @ /usr/src/sys/netpfil/ipfilter/netinet/fil.c:7926 > stack backtrace: > #0 0xffff00000052d394 at witness_debugger+0x60 > #1 0xffff00000052e620 at witness_warn+0x404 > #2 0xffff0000004d4ffc at _callout_stop_safe+0x8c > #3 0xffff0000f7236674 at ipfdetach+0x3c > #4 0xffff0000f723fa4c at ipf_ipf_ioctl+0x788 > #5 0xffff0000f72367e0 at ipfioctl+0x144 > #6 0xffff00000034abd8 at devfs_ioctl+0x100 > #7 0xffff0000005c66a0 at vn_ioctl+0xbc > #8 0xffff00000034b2cc at devfs_ioctl_f+0x24 > #9 0xffff0000005331ec at kern_ioctl+0x2e0 > #10 0xffff000000532eb4 at sys_ioctl+0x140 > #11 0xffff000000880480 at do_el0_sync+0x604 > #12 0xffff0000008579ac at handle_el0_sync+0x4c > > PR: 282478 > Suggested by: markj > Reviewed by: cy > Approved by: emaste (mentor) > MFC after: 1 week > --- > sys/netpfil/ipfilter/netinet/ip_fil_freebsd.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/sys/netpfil/ipfilter/netinet/ip_fil_freebsd.c b/sys/netpfil/ipfilter/netinet/ip_fil_freebsd.c > index bcde0d2c7323..b3dea40c3d8c 100644 > --- a/sys/netpfil/ipfilter/netinet/ip_fil_freebsd.c > +++ b/sys/netpfil/ipfilter/netinet/ip_fil_freebsd.c > @@ -181,7 +181,7 @@ ipf_timer_func(void *arg) > #if 0 > softc->ipf_slow_ch = timeout(ipf_timer_func, softc, hz/2); > #endif > - callout_init(&softc->ipf_slow_ch, 1); > + callout_init_rw(&softc->ipf_slow_ch, &softc->ipf_global.ipf_lk, CALLOUT_SHAREDLOCK); > callout_reset(&softc->ipf_slow_ch, > (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT, > ipf_timer_func, softc); > @@ -221,7 +221,7 @@ ipfattach(ipf_main_softc_t *softc) > softc->ipf_slow_ch = timeout(ipf_timer_func, softc, > (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT); > #endif > - callout_init(&softc->ipf_slow_ch, 1); > + callout_init_rw(&softc->ipf_slow_ch, &softc->ipf_global.ipf_lk, CALLOUT_SHAREDLOCK); > callout_reset(&softc->ipf_slow_ch, (hz / IPF_HZ_DIVIDE) * IPF_HZ_MULT, > ipf_timer_func, softc); > return (0); But this means the callout is now called with the lock held, and I don't see any changes to ipf_timer_func. Hmm, so you now recurse on the lock? You need to take out the locking in ipf_timer_func I think as it is now spurious. You can also axe the #if 0'd code around timeout() while you are at it. -- John Baldwin
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