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* [PR PATCH] libvirt: fix deadlock for musl
@ 2020-10-26 22:45 sirn
  2020-10-26 22:52 ` [PR PATCH] [Updated] " sirn
                   ` (8 more replies)
  0 siblings, 9 replies; 10+ messages in thread
From: sirn @ 2020-10-26 22:45 UTC (permalink / raw)
  To: ml

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There is a new pull request by sirn against master on the void-packages repository

https://github.com/sirn/void-packages libvirt-musl-fix
https://github.com/void-linux/void-packages/pull/25905

libvirt: fix deadlock for musl
libvirt has been broken under musl since v6.3 due to how it uses malloc/free after fork causing a deadlock. When libvirt is in this state, any attempt to connect to it (virsh/virt-manager) will just hangs forever waiting for connection until a `daemon-init` process under libvirt is killed (#23724, [alpine/aports#11602](https://gitlab.alpinelinux.org/alpine/aports/-/issues/11602), [libvirt/libvirt#52](https://gitlab.com/libvirt/libvirt/-/issues/52)).

This PR backport 2 patches from Alpine 3.12 to fix the issue. Going to need some testing on glibc, though.

A patch file from https://github.com/void-linux/void-packages/pull/25905.patch is attached

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From 20364ada6eca920f644c40aee10b9215b5a647c0 Mon Sep 17 00:00:00 2001
From: Kridsada Thanabulpong <sirn@ogsite.net>
Date: Tue, 27 Oct 2020 07:37:50 +0900
Subject: [PATCH] libvirt: fix deadlock for musl

---
 ...avoid-free-when-reset-log-after-fork.patch | 142 ++++++++++++++++++
 .../improve-generic-mass-close-of-fds.patch   | 135 +++++++++++++++++
 srcpkgs/libvirt/template                      |   2 +-
 3 files changed, 278 insertions(+), 1 deletion(-)
 create mode 100644 srcpkgs/libvirt/patches/avoid-free-when-reset-log-after-fork.patch
 create mode 100644 srcpkgs/libvirt/patches/improve-generic-mass-close-of-fds.patch

diff --git a/srcpkgs/libvirt/patches/avoid-free-when-reset-log-after-fork.patch b/srcpkgs/libvirt/patches/avoid-free-when-reset-log-after-fork.patch
new file mode 100644
index 00000000000..06298c02aa6
--- /dev/null
+++ b/srcpkgs/libvirt/patches/avoid-free-when-reset-log-after-fork.patch
@@ -0,0 +1,142 @@
+https://www.redhat.com/archives/libvir-list/2020-August/msg00596.html
+
+Doing malloc/free after fork is techincally not allowed in POSIX and
+deadlocks[1] with musl libc.
+
+[1]: https://gitlab.com/libvirt/libvirt/-/issues/52
+
+Signed-off-by: Natanael Copa <ncopa alpinelinux org>
+---
+ src/util/vircommand.c |  4 ++--
+ src/util/virlog.c     | 44 +++++++++++++++++++++++++++++++++----------
+ src/util/virlog.h     |  1 +
+ 3 files changed, 37 insertions(+), 12 deletions(-)
+
+diff --git a/src/util/vircommand.c b/src/util/vircommand.c
+index 76f7eb9a3d..17e5bb00d3 100644
+--- src/util/vircommand.c
++++ src/util/vircommand.c
+@@ -304,7 +304,7 @@ virFork(void)
+         /* Make sure any hook logging is sent to stderr, since child
+          * process may close the logfile FDs */
+         logprio = virLogGetDefaultPriority();
+-        virLogReset();
++        virLogResetWithoutFree();
+         virLogSetDefaultPriority(logprio);
+
+         /* Clear out all signal handlers from parent so nothing
+@@ -861,7 +861,7 @@ virExec(virCommandPtr cmd)
+        goto fork_error;
+
+     /* Close logging again to ensure no FDs leak to child */
+-    virLogReset();
++    virLogResetWithoutFree();
+
+     if (cmd->env)
+         execve(binary, cmd->args, cmd->env);
+diff --git a/src/util/virlog.c b/src/util/virlog.c
+index 3217e5eb73..3959de5ca7 100644
+--- src/util/virlog.c
++++ src/util/virlog.c
+@@ -108,8 +108,8 @@ static size_t virLogNbOutputs;
+  */
+ static virLogPriority virLogDefaultPriority = VIR_LOG_DEFAULT;
+
+-static void virLogResetFilters(void);
+-static void virLogResetOutputs(void);
++static void virLogResetFilters(bool freemem);
++static void virLogResetOutputs(bool freemem);
+ static void virLogOutputToFd(virLogSourcePtr src,
+                              virLogPriority priority,
+                              const char *filename,
+@@ -284,8 +284,30 @@ virLogReset(void)
+         return -1;
+
+     virLogLock();
+-    virLogResetFilters();
+-    virLogResetOutputs();
++    virLogResetFilters(true);
++    virLogResetOutputs(true);
++    virLogDefaultPriority = VIR_LOG_DEFAULT;
++    virLogUnlock();
++    return 0;
++}
++
++/**
++ * virLogResetWithoutFree:
++ *
++ * Reset the logging module to its default initial state, but avoid doing
++ * free() so it can be used after fork and before exec.
++ *
++ * Returns 0 if successful, and -1 in case or error
++ */
++int
++virLogResetWithoutFree(void)
++{
++    if (virLogInitialize() < 0)
++        return -1;
++
++    virLogLock();
++    virLogResetFilters(false);
++    virLogResetOutputs(false);
+     virLogDefaultPriority = VIR_LOG_DEFAULT;
+     virLogUnlock();
+     return 0;
+@@ -324,9 +346,10 @@ virLogSetDefaultPriority(virLogPriority priority)
+  * Removes the set of logging filters defined.
+  */
+ static void
+-virLogResetFilters(void)
++virLogResetFilters(bool freemem)
+ {
+-    virLogFilterListFree(virLogFilters, virLogNbFilters);
++    if (freemem)
++        virLogFilterListFree(virLogFilters, virLogNbFilters);
+     virLogFilters = NULL;
+     virLogNbFilters = 0;
+     virLogFiltersSerial++;
+@@ -371,9 +394,10 @@ virLogFilterListFree(virLogFilterPtr *list, int count)
+  * Removes the set of logging output defined.
+  */
+ static void
+-virLogResetOutputs(void)
++virLogResetOutputs(bool freemem)
+ {
+-    virLogOutputListFree(virLogOutputs, virLogNbOutputs);
++    if (freemem)
++        virLogOutputListFree(virLogOutputs, virLogNbOutputs);
+     virLogOutputs = NULL;
+     virLogNbOutputs = 0;
+ }
+@@ -1392,7 +1416,7 @@ virLogDefineOutputs(virLogOutputPtr *outputs, size_t noutputs)
+         return -1;
+
+     virLogLock();
+-    virLogResetOutputs();
++    virLogResetOutputs(true);
+
+ #if HAVE_SYSLOG_H
+     /* syslog needs to be special-cased, since it keeps the fd in private */
+@@ -1435,7 +1459,7 @@ virLogDefineFilters(virLogFilterPtr *filters, size_t nfilters)
+         return -1;
+
+     virLogLock();
+-    virLogResetFilters();
++    virLogResetFilters(true);
+     virLogFilters = filters;
+     virLogNbFilters = nfilters;
+     virLogUnlock();
+diff --git a/src/util/virlog.h b/src/util/virlog.h
+index 984a9d5a43..69f7b1ef94 100644
+--- src/util/virlog.h
++++ src/util/virlog.h
+@@ -168,6 +168,7 @@ void virLogSetDefaultOutput(const char *fname, bool godaemon, bool privileged);
+ void virLogLock(void);
+ void virLogUnlock(void);
+ int virLogReset(void);
++int virLogResetWithoutFree(void);
+ int virLogParseDefaultPriority(const char *priority);
+ int virLogPriorityFromSyslog(int priority);
+ void virLogMessage(virLogSourcePtr source,
+--
+2.28.0
diff --git a/srcpkgs/libvirt/patches/improve-generic-mass-close-of-fds.patch b/srcpkgs/libvirt/patches/improve-generic-mass-close-of-fds.patch
new file mode 100644
index 00000000000..bf2983401d7
--- /dev/null
+++ b/srcpkgs/libvirt/patches/improve-generic-mass-close-of-fds.patch
@@ -0,0 +1,135 @@
+https://www.redhat.com/archives/libvir-list/2020-August/msg00598.html
+
+Add a portable generic implementation of virMassClose as fallback on
+
+non-FreeBSD and non-glibc.
+
+This implementation uses poll(2) to look for open files to keep
+performance reasonable while not using any mallocs.
+
+This solves a deadlock with musl libc.
+
+Signed-off-by: Natanael Copa <ncopa alpinelinux org>
+---
+ src/util/vircommand.c | 76 +++++++++++++++++++++++++++++++++----------
+ 1 file changed, 58 insertions(+), 18 deletions(-)
+
+diff --git a/src/util/vircommand.c b/src/util/vircommand.c
+index 17e5bb00d3..06579cfb44 100644
+--- src/util/vircommand.c
++++ src/util/vircommand.c
+@@ -443,7 +443,7 @@ virExecCommon(virCommandPtr cmd, gid_t *groups, int ngroups)
+     return 0;
+ }
+
+-# ifdef __linux__
++# if defined(__linux__) && defined(__GLIBC__)
+ /* On Linux, we can utilize procfs and read the table of opened
+  * FDs and selectively close only those FDs we don't want to pass
+  * onto child process (well, the one we will exec soon since this
+@@ -482,17 +482,7 @@ virCommandMassCloseGetFDsLinux(virCommandPtr cmd G_GNUC_UNUSED,
+     VIR_DIR_CLOSE(dp);
+     return ret;
+ }
+-
+-# else /* !__linux__ */
+-
+-static int
+-virCommandMassCloseGetFDsGeneric(virCommandPtr cmd G_GNUC_UNUSED,
+-                                 virBitmapPtr fds)
+-{
+-    virBitmapSetAll(fds);
+-    return 0;
+-}
+-# endif /* !__linux__ */
++# endif /* __linux__ && __GLIBC__ */
+
+ # ifdef __FreeBSD__
+
+@@ -546,7 +536,7 @@ virCommandMassClose(virCommandPtr cmd,
+     return 0;
+ }
+
+-# else /* ! __FreeBSD__ */
++# elif defined(__GLIBC__)  /* ! __FreeBSD__ */
+
+ static int
+ virCommandMassClose(virCommandPtr cmd,
+@@ -574,13 +564,8 @@ virCommandMassClose(virCommandPtr cmd,
+     if (!(fds = virBitmapNew(openmax)))
+         return -1;
+
+-#  ifdef __linux__
+     if (virCommandMassCloseGetFDsLinux(cmd, fds) < 0)
+         return -1;
+-#  else
+-    if (virCommandMassCloseGetFDsGeneric(cmd, fds) < 0)
+-        return -1;
+-#  endif
+
+     fd = virBitmapNextSetBit(fds, 2);
+     for (; fd >= 0; fd = virBitmapNextSetBit(fds, fd)) {
+@@ -598,6 +583,61 @@ virCommandMassClose(virCommandPtr cmd,
+     return 0;
+ }
+
++#else /* ! __FreeBSD__ && ! __GLIBC__ */
++static int
++virCommandMassClose(virCommandPtr cmd,
++                    int childin,
++                    int childout,
++                    int childerr)
++{
++    static struct pollfd pfds[1024];
++    int fd = 0;
++    int i, total;
++    int max_fd = sysconf(_SC_OPEN_MAX);
++
++    if (max_fd < 0) {
++        virReportSystemError(errno, "%s", _("sysconf(_SC_OPEN_MAX) failed"));
++        return -1;
++    }
++
++    total = max_fd - fd;
++    for (i = 0; i < (total < 1024 ? total : 1024); i++)
++        pfds[i].events = 0;
++
++    while (fd < max_fd) {
++        int nfds, r = 0;
++
++        total = max_fd - fd;
++        nfds =  total < 1024 ? total : 1024;
++
++        for (i = 0; i < nfds; i++)
++            pfds[i].fd = fd + i;
++
++        do {
++            r = poll(pfds, nfds, 0);
++        } while (r == -1 && errno == EINTR);
++
++        if (r < 0) {
++            virReportSystemError(errno, "%s", _("poll() failed"));
++            return -1;
++        }
++
++        for (i = 0; i < nfds; i++)
++            if (pfds[i].revents != POLLNVAL) {
++                if (pfds[i].fd == childin || pfds[i].fd == childout || pfds[i].fd == childerr)
++                    continue;
++                if (!virCommandFDIsSet(cmd, pfds[i].fd)) {
++                    VIR_MASS_CLOSE(pfds[i].fd);
++                } else if (virSetInherit(pfds[i].fd, true) < 0) {
++                    virReportSystemError(errno, _("failed to preserve fd %d"), pfds[i].fd);
++                    return -1;
++                }
++            }
++        fd += nfds;
++    }
++    return 0;
++}
++
+ # endif /* ! __FreeBSD__ */
+
+ /*
+--
+22.28.0
diff --git a/srcpkgs/libvirt/template b/srcpkgs/libvirt/template
index cc07eca3d0b..2f2d746c955 100644
--- a/srcpkgs/libvirt/template
+++ b/srcpkgs/libvirt/template
@@ -1,7 +1,7 @@
 # Template file for 'libvirt'
 pkgname=libvirt
 version=6.6.0
-revision=4
+revision=5
 build_wrksrc="build"
 build_style=gnu-configure
 configure_script="../configure"

^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2021-01-02  3:41 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-10-26 22:45 [PR PATCH] libvirt: fix deadlock for musl sirn
2020-10-26 22:52 ` [PR PATCH] [Updated] " sirn
2020-11-06 17:33 ` ahesford
2020-11-08 10:27 ` [PR PATCH] [Updated] " sirn
2020-11-08 10:36 ` sirn
2020-11-17 20:38 ` Logarithmus
2020-11-17 20:38 ` Logarithmus
2020-11-17 20:40 ` Logarithmus
2020-12-23 17:35 ` gch1p
2021-01-02  3:41 ` [PR PATCH] [Closed]: " ahesford

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