Date: Fri, 10 Jul 2020 11:25:52 +0200 From: Mateusz Guzik <mjguzik@gmail.com> To: Peter Holm <pho@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r363069 - head/sys/kern Message-ID: <CAGudoHEyYmyVYm3VqTZZ9zybW6o3O1M4Rm9gTGrsBcSfRBwj3A@mail.gmail.com> In-Reply-To: <CAGudoHGo2=xqcaH4yLb1dWBCORrj8tBiWOwfoB37q=vrVh_FWA@mail.gmail.com> References: <202007100647.06A6lwCE015392@repo.freebsd.org> <20200710090131.GA34716@x8.osted.lan> <CAGudoHGo2=xqcaH4yLb1dWBCORrj8tBiWOwfoB37q=vrVh_FWA@mail.gmail.com>
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On 7/10/20, Mateusz Guzik <mjguzik@gmail.com> wrote: > On 7/10/20, Peter Holm <pho@freebsd.org> wrote: >> On Fri, Jul 10, 2020 at 06:47:58AM +0000, Mateusz Guzik wrote: >>> Author: mjg >>> Date: Fri Jul 10 06:47:58 2020 >>> New Revision: 363069 >>> URL: https://svnweb.freebsd.org/changeset/base/363069 >>> >>> Log: >>> vfs: depessimize getfsstat when only the count is requested >>> >>> This avoids relocking mountlist_mtx for each entry. >>> >>> Modified: >>> head/sys/kern/vfs_syscalls.c >>> >>> Modified: head/sys/kern/vfs_syscalls.c >>> ============================================================================== >>> --- head/sys/kern/vfs_syscalls.c Fri Jul 10 06:46:42 2020 (r363068) >> >> Could this one be yours? >> >> 20200710 09:46:31 all (267/723): procfs.sh >> panic: lock (sleep mutex) mountlist not locked @ kern/vfs_syscalls.c:561 >> cpuid = 4 >> time = 1594367192 >> KDB: stack backtrace: >> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame >> 0xfffffe00377a6910 >> vpanic() at vpanic+0x182/frame 0xfffffe00377a6960 >> panic() at panic+0x43/frame 0xfffffe00377a69c0 >> witness_unlock() at witness_unlock+0x147/frame 0xfffffe00377a6a00 >> __mtx_unlock_flags() at __mtx_unlock_flags+0x4d/frame 0xfffffe00377a6a30 >> kern_getfsstat() at kern_getfsstat+0x40b/frame 0xfffffe00377a6ab0 >> sys_getfsstat() at sys_getfsstat+0x22/frame 0xfffffe00377a6ad0 >> amd64_syscall() at amd64_syscall+0x159/frame 0xfffffe00377a6bf0 >> fast_syscall_common() at fast_syscall_common+0x101/frame >> 0xfffffe00377a6bf0 >> --- syscall (557, FreeBSD ELF64, sys_getfsstat), rip = 0x80032db1a, rsp = >> 0x7fffffffd738, rbp = 0x7fffffffd790 --- >> KDB: enter: panic >> >> https://people.freebsd.org/~pho/stress/log/mjguzik030.txt >> > > Does this fix it for you? > > diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c > index f37a54809e24..2caf09f3412c 100644 > --- a/sys/kern/vfs_syscalls.c > +++ b/sys/kern/vfs_syscalls.c > @@ -551,7 +551,7 @@ kern_getfsstat(struct thread *td, struct statfs > **buf, size_t bufsize, > > if (count == maxcount) { > vfs_unbusy(mp); > - break; > + goto out; > } > > mtx_lock(&mountlist_mtx); > Reproduced and verified the above fixes it, committed here: https://svnweb.freebsd.org/changeset/base/363072 -- Mateusz Guzik <mjguzik gmail.com>
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