I have read through the code in exec_mmap and I do not see anything
that depends on sighand or the sighand lock, or on signals in anyway
so this should be safe.
This rearrangement of code has two significant benefits. It makes
the determination of passing the point of no return by testing bprm->mm
accurate. All failures prior to that point in flush_old_exec are
either truly recoverable or they are fatal.
Further this consolidates all of the possible indefinite waits for
userspace together at the top of flush_old_exec. The possible wait
for a ptracer on PTRACE_EVENT_EXIT, the possible wait for a page fault
to be resolved in clear_child_tid, and the possible wait for a page
fault in exit_robust_list.
This consolidation allows the creation of a mutex to replace
cred_guard_mutex that is not held over possible indefinite userspace
waits. Which will allow removing deadlock scenarios from the kernel.
Signed-off-by: "Eric W. Biederman" <ebiederm(a)xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Reviewed-by: Kirill Tkhai <ktkhai(a)virtuozzo.com>
---
fs/exec.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 215d86f7..d820a72 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1272,18 +1272,6 @@ int flush_old_exec(struct linux_binprm * bprm)
if (retval)
goto out;
-#ifdef CONFIG_POSIX_TIMERS
- exit_itimers(me->signal);
- flush_itimer_signals();
-#endif
-
- /*
- * Make the signal table private.
- */
- retval = unshare_sighand(me);
- if (retval)
- goto out;
-
/*
* Must be called _before_ exec_mmap() as bprm->mm is
* not visibile until then. This also enables the update
@@ -1307,6 +1295,18 @@ int flush_old_exec(struct linux_binprm * bprm)
*/
bprm->mm = NULL;
+#ifdef CONFIG_POSIX_TIMERS
+ exit_itimers(me->signal);
+ flush_itimer_signals();
+#endif
+
+ /*
+ * Make the signal table private.
+ */
+ retval = unshare_sighand(me);
+ if (retval)
+ goto out;
+
set_fs(USER_DS);
me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
PF_NOFREEZE | PF_NO_SETAFFINITY);
--
1.9.1
These functions have very little to do with de_thread move them out
of de_thread an into flush_old_exec proper so it can be more clearly
seen what flush_old_exec is doing.
Signed-off-by: "Eric W. Biederman" <ebiederm(a)xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Christian Brauner <christian.brauner(a)ubuntu.com>
Reviewed-by: Kirill Tkhai <ktkhai(a)virtuozzo.com>
---
fs/exec.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index ff74b9a..215d86f7 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1189,11 +1189,6 @@ static int de_thread(struct task_struct *tsk)
/* we have changed execution domain */
tsk->exit_signal = SIGCHLD;
-#ifdef CONFIG_POSIX_TIMERS
- exit_itimers(sig);
- flush_itimer_signals();
-#endif
-
BUG_ON(!thread_group_leader(tsk));
return 0;
@@ -1277,6 +1272,11 @@ int flush_old_exec(struct linux_binprm * bprm)
if (retval)
goto out;
+#ifdef CONFIG_POSIX_TIMERS
+ exit_itimers(me->signal);
+ flush_itimer_signals();
+#endif
+
/*
* Make the signal table private.
*/
--
1.9.1
This makes the code clearer and makes it easier to implement a mutex
that is not taken over any locations that may block indefinitely waiting
for userspace.
Signed-off-by: "Eric W. Biederman" <ebiederm(a)xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Christian Brauner <christian.brauner(a)ubuntu.com>
Reviewed-by: Kirill Tkhai <ktkhai(a)virtuozzo.com>
---
fs/exec.c | 39 ++++++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 13 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index c3f3479..ff74b9a 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1194,6 +1194,23 @@ static int de_thread(struct task_struct *tsk)
flush_itimer_signals();
#endif
+ BUG_ON(!thread_group_leader(tsk));
+ return 0;
+
+killed:
+ /* protects against exit_notify() and __exit_signal() */
+ read_lock(&tasklist_lock);
+ sig->group_exit_task = NULL;
+ sig->notify_count = 0;
+ read_unlock(&tasklist_lock);
+ return -EAGAIN;
+}
+
+
+static int unshare_sighand(struct task_struct *me)
+{
+ struct sighand_struct *oldsighand = me->sighand;
+
if (refcount_read(&oldsighand->count) != 1) {
struct sighand_struct *newsighand;
/*
@@ -1210,23 +1227,13 @@ static int de_thread(struct task_struct *tsk)
write_lock_irq(&tasklist_lock);
spin_lock(&oldsighand->siglock);
- rcu_assign_pointer(tsk->sighand, newsighand);
+ rcu_assign_pointer(me->sighand, newsighand);
spin_unlock(&oldsighand->siglock);
write_unlock_irq(&tasklist_lock);
__cleanup_sighand(oldsighand);
}
-
- BUG_ON(!thread_group_leader(tsk));
return 0;
-
-killed:
- /* protects against exit_notify() and __exit_signal() */
- read_lock(&tasklist_lock);
- sig->group_exit_task = NULL;
- sig->notify_count = 0;
- read_unlock(&tasklist_lock);
- return -EAGAIN;
}
char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk)
@@ -1264,14 +1271,20 @@ int flush_old_exec(struct linux_binprm * bprm)
int retval;
/*
- * Make sure we have a private signal table and that
- * we are unassociated from the previous thread group.
+ * Make this the only thread in the thread group.
*/
retval = de_thread(me);
if (retval)
goto out;
/*
+ * Make the signal table private.
+ */
+ retval = unshare_sighand(me);
+ if (retval)
+ goto out;
+
+ /*
* Must be called _before_ exec_mmap() as bprm->mm is
* not visibile until then. This also enables the update
* to be lockless.
--
1.9.1
Make it clear that current only needs to be computed once in
flush_old_exec. This may have some efficiency improvements and it
makes the code easier to change.
Signed-off-by: "Eric W. Biederman" <ebiederm(a)xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Christian Brauner <christian.brauner(a)ubuntu.com>
Reviewed-by: Kirill Tkhai <ktkhai(a)virtuozzo.com>
---
fs/exec.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index db17be5..c3f3479 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1260,13 +1260,14 @@ void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
*/
int flush_old_exec(struct linux_binprm * bprm)
{
+ struct task_struct *me = current;
int retval;
/*
* Make sure we have a private signal table and that
* we are unassociated from the previous thread group.
*/
- retval = de_thread(current);
+ retval = de_thread(me);
if (retval)
goto out;
@@ -1294,10 +1295,10 @@ int flush_old_exec(struct linux_binprm * bprm)
bprm->mm = NULL;
set_fs(USER_DS);
- current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
+ me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
PF_NOFREEZE | PF_NO_SETAFFINITY);
flush_thread();
- current->personality &= ~bprm->per_clear;
+ me->personality &= ~bprm->per_clear;
/*
* We have to apply CLOEXEC before we change whether the process is
@@ -1305,7 +1306,7 @@ int flush_old_exec(struct linux_binprm * bprm)
* trying to access the should-be-closed file descriptors of a process
* undergoing exec(2).
*/
- do_close_on_exec(current->files);
+ do_close_on_exec(me->files);
return 0;
out:
--
1.9.1
Hello,
We ran automated tests on a recent commit from this kernel tree:
Kernel repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
Commit: bea94317c526 - Linux 5.5.11-rc3
The results of these automated tests are provided below.
Overall result: FAILED (see details below)
Merge: OK
Compile: OK
Tests: FAILED
All kernel binaries, config files, and logs are available for download here:
https://cki-artifacts.s3.us-east-2.amazonaws.com/index.html?prefix=dataware…
One or more kernel tests failed:
ppc64le:
❌ LTP
We hope that these logs can help you find the problem quickly. For the full
detail on our testing procedures, please scroll to the bottom of this message.
Please reply to this email if you have any questions about the tests that we
ran or if you have any suggestions on how to make future tests more effective.
,-. ,-.
( C ) ( K ) Continuous
`-',-.`-' Kernel
( I ) Integration
`-'
______________________________________________________________________________
Compile testing
---------------
We compiled the kernel for 4 architectures:
aarch64:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
ppc64le:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
s390x:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
x86_64:
make options: -j30 INSTALL_MOD_STRIP=1 targz-pkg
Hardware testing
----------------
We booted each kernel and ran the following tests:
aarch64:
Host 1:
✅ Boot test
✅ Podman system integration test - as root
✅ Podman system integration test - as user
✅ LTP
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ AMTU (Abstract Machine Test Utility)
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking socket: fuzz
✅ Networking sctp-auth: sockopts test
✅ Networking: igmp conformance test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - transport
✅ Networking ipsec: basic netns - tunnel
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ ALSA PCM loopback test
✅ ALSA Control (mixer) Userspace Element test
✅ storage: SCSI VPD
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm - DaCapo Benchmark Suite
🚧 ✅ jvm - jcstress tests
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ❌ audit: audit testsuite test
🚧 ✅ iotop: sanity
🚧 ✅ Usex - version 1.9-29
🚧 ✅ storage: dm/common
Host 2:
✅ Boot test
✅ xfstests - ext4
✅ xfstests - xfs
✅ selinux-policy: serge-testsuite
✅ lvm thinp sanity
✅ storage: software RAID testing
🚧 ✅ Storage blktests
ppc64le:
Host 1:
✅ Boot test
✅ xfstests - ext4
✅ xfstests - xfs
✅ selinux-policy: serge-testsuite
✅ lvm thinp sanity
✅ storage: software RAID testing
🚧 ✅ IPMI driver test
🚧 ✅ IPMItool loop stress test
🚧 ✅ Storage blktests
Host 2:
✅ Boot test
✅ Podman system integration test - as root
✅ Podman system integration test - as user
❌ LTP
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ AMTU (Abstract Machine Test Utility)
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking socket: fuzz
✅ Networking sctp-auth: sockopts test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - tunnel
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ ALSA PCM loopback test
✅ ALSA Control (mixer) Userspace Element test
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm - DaCapo Benchmark Suite
🚧 ✅ jvm - jcstress tests
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ❌ audit: audit testsuite test
🚧 ✅ iotop: sanity
🚧 ✅ Usex - version 1.9-29
🚧 ✅ storage: dm/common
s390x:
Host 1:
✅ Boot test
✅ selinux-policy: serge-testsuite
🚧 ✅ Storage blktests
Host 2:
⚡ Internal infrastructure issues prevented one or more tests (marked
with ⚡⚡⚡) from running on this architecture.
This is not the fault of the kernel that was tested.
✅ Boot test
⚡⚡⚡ Podman system integration test - as root
✅ Podman system integration test - as user
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking sctp-auth: sockopts test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - transport
✅ Networking ipsec: basic netns - tunnel
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm - DaCapo Benchmark Suite
🚧 ✅ jvm - jcstress tests
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ❌ audit: audit testsuite test
🚧 ✅ iotop: sanity
🚧 ✅ storage: dm/common
x86_64:
Host 1:
✅ Boot test
✅ Storage SAN device stress - megaraid_sas
Host 2:
✅ Boot test
✅ Storage SAN device stress - mpt3sas driver
Host 3:
✅ Boot test
✅ Podman system integration test - as root
✅ Podman system integration test - as user
✅ LTP
✅ Loopdev Sanity
✅ Memory function: memfd_create
✅ AMTU (Abstract Machine Test Utility)
✅ Networking bridge: sanity
✅ Ethernet drivers sanity
✅ Networking MACsec: sanity
✅ Networking socket: fuzz
✅ Networking sctp-auth: sockopts test
✅ Networking: igmp conformance test
✅ Networking route: pmtu
✅ Networking route_func - local
✅ Networking route_func - forward
✅ Networking TCP: keepalive test
✅ Networking UDP: socket
✅ Networking tunnel: geneve basic test
✅ Networking tunnel: gre basic
✅ L2TP basic test
✅ Networking tunnel: vxlan basic
✅ Networking ipsec: basic netns - transport
✅ Networking ipsec: basic netns - tunnel
✅ httpd: mod_ssl smoke sanity
✅ tuned: tune-processes-through-perf
✅ pciutils: sanity smoke test
✅ ALSA PCM loopback test
✅ ALSA Control (mixer) Userspace Element test
✅ storage: SCSI VPD
✅ trace: ftrace/tracer
🚧 ✅ CIFS Connectathon
🚧 ✅ POSIX pjd-fstest suites
🚧 ✅ jvm - DaCapo Benchmark Suite
🚧 ✅ jvm - jcstress tests
🚧 ✅ Memory function: kaslr
🚧 ✅ LTP: openposix test suite
🚧 ✅ Networking vnic: ipvlan/basic
🚧 ❌ audit: audit testsuite test
🚧 ✅ iotop: sanity
🚧 ✅ Usex - version 1.9-29
🚧 ✅ storage: dm/common
Host 4:
✅ Boot test
✅ xfstests - ext4
✅ xfstests - xfs
✅ selinux-policy: serge-testsuite
✅ lvm thinp sanity
✅ storage: software RAID testing
✅ stress: stress-ng
🚧 ✅ IOMMU boot test
🚧 ✅ IPMI driver test
🚧 ✅ IPMItool loop stress test
🚧 ✅ Storage blktests
Test sources: https://github.com/CKI-project/tests-beaker
💚 Pull requests are welcome for new tests or improvements to existing tests!
Aborted tests
-------------
Tests that didn't complete running successfully are marked with ⚡⚡⚡.
If this was caused by an infrastructure issue, we try to mark that
explicitly in the report.
Waived tests
------------
If the test run included waived tests, they are marked with 🚧. Such tests are
executed but their results are not taken into account. Tests are waived when
their results are not reliable enough, e.g. when they're just introduced or are
being fixed.
Testing timeout
---------------
We aim to provide a report within reasonable timeframe. Tests that haven't
finished running yet are marked with ⏱.
Hi
[This is an automated email]
This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all
The bot has tested the following trees: v5.5.10, v5.4.26, v4.19.111, v4.14.173, v4.9.216, v4.4.216.
v5.5.10: Build OK!
v5.4.26: Build OK!
v4.19.111: Build OK!
v4.14.173: Build OK!
v4.9.216: Failed to apply! Possible dependencies:
Unable to calculate
v4.4.216: Failed to apply! Possible dependencies:
Unable to calculate
NOTE: The patch will not be queued to stable trees until it is upstream.
How should we proceed with this patch?
--
Thanks
Sasha