From: Dmitry Vyukov <dvyukov(a)google.com>
POSIX timers using the CLOCK_PROCESS_CPUTIME_ID clock prefer the main
thread of a thread group for signal delivery. However, this has a
significant downside: it requires waking up a potentially idle thread.
Instead, prefer to deliver signals to the current thread (in the same
thread group) if SIGEV_THREAD_ID is not set by the user. This does not
change guaranteed semantics, since POSIX process CPU time timers have
never guaranteed that signal delivery is to a specific thread (without
SIGEV_THREAD_ID set).
The effect is that we no longer wake up potentially idle threads, and
the kernel is no longer biased towards delivering the timer signal to
any particular thread (which better distributes the timer signals esp.
when multiple timers fire concurrently).
Signed-off-by: Dmitry Vyukov <dvyukov(a)google.com>
Suggested-by: Oleg Nesterov <oleg(a)redhat.com>
Reviewed-by: Oleg Nesterov <oleg(a)redhat.com>
Signed-off-by: Marco Elver <elver(a)google.com>
---
v6:
- Split test from this patch.
- Update wording on what this patch aims to improve.
v5:
- Rebased onto v6.2.
v4:
- Restructured checks in send_sigqueue() as suggested.
v3:
- Switched to the completely different implementation (much simpler)
based on the Oleg's idea.
RFC v2:
- Added additional Cc as Thomas asked.
---
kernel/signal.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 8cb28f1df294..605445fa27d4 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1003,8 +1003,7 @@ static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
/*
* Now find a thread we can wake up to take the signal off the queue.
*
- * If the main thread wants the signal, it gets first crack.
- * Probably the least surprising to the average bear.
+ * Try the suggested task first (may or may not be the main thread).
*/
if (wants_signal(sig, p))
t = p;
@@ -1970,8 +1969,23 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
ret = -1;
rcu_read_lock();
+ /*
+ * This function is used by POSIX timers to deliver a timer signal.
+ * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID
+ * set), the signal must be delivered to the specific thread (queues
+ * into t->pending).
+ *
+ * Where type is not PIDTYPE_PID, signals must just be delivered to the
+ * current process. In this case, prefer to deliver to current if it is
+ * in the same thread group as the target, as it avoids unnecessarily
+ * waking up a potentially idle task.
+ */
t = pid_task(pid, type);
- if (!t || !likely(lock_task_sighand(t, &flags)))
+ if (!t)
+ goto ret;
+ if (type != PIDTYPE_PID && same_thread_group(t, current))
+ t = current;
+ if (!likely(lock_task_sighand(t, &flags)))
goto ret;
ret = 1; /* the signal is ignored */
@@ -1993,6 +2007,11 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
q->info.si_overrun = 0;
signalfd_notify(t, sig);
+ /*
+ * If the type is not PIDTYPE_PID, we just use shared_pending, which
+ * won't guarantee that the specified task will receive the signal, but
+ * is sufficient if t==current in the common case.
+ */
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
list_add_tail(&q->list, &pending->list);
sigaddset(&pending->signal, sig);
--
2.40.0.rc1.284.g88254d51c5-goog
From: Zi Yan <ziy(a)nvidia.com>
Hi all,
File folio supports any order and people would like to support flexible orders
for anonymous folio[1] too. Currently, split_huge_page() only splits a huge
page to order-0 pages, but splitting to orders higher than 0 is also useful.
This patchset adds support for splitting a huge page to any lower order pages
and uses it during file folio truncate operations.
The patchset is on top of mm-everything-2023-03-27-21-20.
Changelog
===
Since v2
---
1. Fixed an issue in __split_page_owner() introduced during my rebase
Since v1
---
1. Changed split_page_memcg() and split_page_owner() parameter to use order
2. Used folio_test_pmd_mappable() in place of the equivalent code
Details
===
* Patch 1 changes split_page_memcg() to use order instead of nr_pages
* Patch 2 changes split_page_owner() to use order instead of nr_pages
* Patch 3 and 4 add new_order parameter split_page_memcg() and
split_page_owner() and prepare for upcoming changes.
* Patch 5 adds split_huge_page_to_list_to_order() to split a huge page
to any lower order. The original split_huge_page_to_list() calls
split_huge_page_to_list_to_order() with new_order = 0.
* Patch 6 uses split_huge_page_to_list_to_order() in large pagecache folio
truncation instead of split the large folio all the way down to order-0.
* Patch 7 adds a test API to debugfs and test cases in
split_huge_page_test selftests.
Comments and/or suggestions are welcome.
[1] https://lore.kernel.org/linux-mm/Y%2FblF0GIunm+pRIC@casper.infradead.org/
Zi Yan (7):
mm/memcg: use order instead of nr in split_page_memcg()
mm/page_owner: use order instead of nr in split_page_owner()
mm: memcg: make memcg huge page split support any order split.
mm: page_owner: add support for splitting to any order in split
page_owner.
mm: thp: split huge page to any lower order pages.
mm: truncate: split huge page cache page to a non-zero order if
possible.
mm: huge_memory: enable debugfs to split huge pages to any order.
include/linux/huge_mm.h | 10 +-
include/linux/memcontrol.h | 4 +-
include/linux/page_owner.h | 10 +-
mm/huge_memory.c | 137 ++++++++---
mm/memcontrol.c | 10 +-
mm/page_alloc.c | 8 +-
mm/page_owner.c | 8 +-
mm/truncate.c | 21 +-
.../selftests/mm/split_huge_page_test.c | 225 +++++++++++++++++-
9 files changed, 365 insertions(+), 68 deletions(-)
--
2.39.2
Here's a follow-up from my RFC series last year:
https://lore.kernel.org/lkml/20221004093131.40392-1-thuth@redhat.com/T/
and from v1 earlier this year:
https://lore.kernel.org/kvm/20230712075910.22480-1-thuth@redhat.com/
Basic idea of this series is now to use the kselftest_harness.h
framework to get TAP output in the tests, so that it is easier
for the user to see what is going on, and e.g. to be able to
detect whether a certain test is part of the test binary or not
(which is useful when tests get extended in the course of time).
v2:
- Dropped the "Rename the ASSERT_EQ macro" patch (already merged)
- Split the fixes in the sync_regs_test into separate patches
(see the first two patches)
- Introduce the KVM_ONE_VCPU_TEST_SUITE() macro as suggested
by Sean (see third patch) and use it in the following patches
- Add a new patch to convert vmx_pmu_caps_test.c, too
Thomas Huth (7):
KVM: selftests: x86: sync_regs_test: Use vcpu_run() where appropriate
KVM: selftests: x86: sync_regs_test: Get regs structure before
modifying it
KVM: selftests: Add a macro to define a test with one vcpu
KVM: selftests: x86: Use TAP interface in the sync_regs test
KVM: selftests: x86: Use TAP interface in the fix_hypercall test
KVM: selftests: x86: Use TAP interface in the vmx_pmu_caps test
KVM: selftests: x86: Use TAP interface in the userspace_msr_exit test
.../selftests/kvm/include/kvm_test_harness.h | 35 +++++
.../selftests/kvm/x86_64/fix_hypercall_test.c | 27 ++--
.../selftests/kvm/x86_64/sync_regs_test.c | 121 +++++++++++++-----
.../kvm/x86_64/userspace_msr_exit_test.c | 19 +--
.../selftests/kvm/x86_64/vmx_pmu_caps_test.c | 50 ++------
5 files changed, 160 insertions(+), 92 deletions(-)
create mode 100644 tools/testing/selftests/kvm/include/kvm_test_harness.h
--
2.41.0
This introduces signal->exec_bprm, which is used to
fix the case when at least one of the sibling threads
is traced, and therefore the trace process may dead-lock
in ptrace_attach, but de_thread will need to wait for the
tracer to continue execution.
The solution is to detect this situation and allow
ptrace_attach to continue by temporarily releasing the
cred_guard_mutex, while de_thread() is still waiting for
traced zombies to be eventually released by the tracer.
In the case of the thread group leader we only have to wait
for the thread to become a zombie, which may also need
co-operation from the tracer due to PTRACE_O_TRACEEXIT.
When a tracer wants to ptrace_attach a task that already
is in execve, we simply retry the ptrace_may_access
check while temporarily installing the new credentials
and dumpability which are about to be used after execve
completes. If the ptrace_attach happens on a thread that
is a sibling-thread of the thread doing execve, it is
sufficient to check against the old credentials, as this
thread will be waited for, before the new credentials are
installed.
Other threads die quickly since the cred_guard_mutex is
released, but a deadly signal is already pending. In case
the mutex_lock_killable misses the signal, the non-zero
current->signal->exec_bprm makes sure they release the
mutex immediately and return with -ERESTARTNOINTR.
This means there is no API change, unlike the previous
version of this patch which was discussed here:
https://lore.kernel.org/lkml/b6537ae6-31b1-5c50-f32b-8b8332ace882@hotmail.d…
See tools/testing/selftests/ptrace/vmaccess.c
for a test case that gets fixed by this change.
Note that since the test case was originally designed to
test the ptrace_attach returning an error in this situation,
the test expectation needed to be adjusted, to allow the
API to succeed at the first attempt.
Signed-off-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de>
---
fs/exec.c | 69 ++++++++++++++++-------
fs/proc/base.c | 6 ++
include/linux/cred.h | 1 +
include/linux/sched/signal.h | 18 ++++++
kernel/cred.c | 28 +++++++--
kernel/ptrace.c | 32 +++++++++++
kernel/seccomp.c | 12 +++-
tools/testing/selftests/ptrace/vmaccess.c | 23 +++++---
8 files changed, 155 insertions(+), 34 deletions(-)
v10: Changes to previous version, make the PTRACE_ATTACH
retun -EAGAIN, instead of execve return -ERESTARTSYS.
Added some lessions learned to the description.
v11: Check old and new credentials in PTRACE_ATTACH again without
changing the API.
Note: I got actually one response from an automatic checker to the v11 patch,
https://lore.kernel.org/lkml/202107121344.wu68hEPF-lkp@intel.com/
which is complaining about:
>> kernel/ptrace.c:425:26: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct cred const *old_cred @@ got struct cred const [noderef] __rcu *real_cred @@
417 struct linux_binprm *bprm = task->signal->exec_bprm;
418 const struct cred *old_cred;
419 struct mm_struct *old_mm;
420
421 retval = down_write_killable(&task->signal->exec_update_lock);
422 if (retval)
423 goto unlock_creds;
424 task_lock(task);
> 425 old_cred = task->real_cred;
v12: Essentially identical to v11.
- Fixed a minor merge conflict in linux v5.17, and fixed the
above mentioned nit by adding __rcu to the declaration.
- re-tested the patch with all linux versions from v5.11 to v6.6
v10 was an alternative approach which did imply an API change.
But I would prefer to avoid such an API change.
The difficult part is getting the right dumpability flags assigned
before de_thread starts, hope you like this version.
If not, the v10 is of course also acceptable.
Thanks
Bernd.
diff --git a/fs/exec.c b/fs/exec.c
index 2f2b0acec4f0..902d3b230485 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1041,11 +1041,13 @@ static int exec_mmap(struct mm_struct *mm)
return 0;
}
-static int de_thread(struct task_struct *tsk)
+static int de_thread(struct task_struct *tsk, struct linux_binprm *bprm)
{
struct signal_struct *sig = tsk->signal;
struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
+ struct task_struct *t = tsk;
+ bool unsafe_execve_in_progress = false;
if (thread_group_empty(tsk))
goto no_thread_group;
@@ -1068,6 +1070,19 @@ static int de_thread(struct task_struct *tsk)
if (!thread_group_leader(tsk))
sig->notify_count--;
+ while_each_thread(tsk, t) {
+ if (unlikely(t->ptrace)
+ && (t != tsk->group_leader || !t->exit_state))
+ unsafe_execve_in_progress = true;
+ }
+
+ if (unlikely(unsafe_execve_in_progress)) {
+ spin_unlock_irq(lock);
+ sig->exec_bprm = bprm;
+ mutex_unlock(&sig->cred_guard_mutex);
+ spin_lock_irq(lock);
+ }
+
while (sig->notify_count) {
__set_current_state(TASK_KILLABLE);
spin_unlock_irq(lock);
@@ -1158,6 +1173,11 @@ static int de_thread(struct task_struct *tsk)
release_task(leader);
}
+ if (unlikely(unsafe_execve_in_progress)) {
+ mutex_lock(&sig->cred_guard_mutex);
+ sig->exec_bprm = NULL;
+ }
+
sig->group_exec_task = NULL;
sig->notify_count = 0;
@@ -1169,6 +1189,11 @@ static int de_thread(struct task_struct *tsk)
return 0;
killed:
+ if (unlikely(unsafe_execve_in_progress)) {
+ mutex_lock(&sig->cred_guard_mutex);
+ sig->exec_bprm = NULL;
+ }
+
/* protects against exit_notify() and __exit_signal() */
read_lock(&tasklist_lock);
sig->group_exec_task = NULL;
@@ -1253,6 +1278,24 @@ int begin_new_exec(struct linux_binprm * bprm)
if (retval)
return retval;
+ /* If the binary is not readable then enforce mm->dumpable=0 */
+ would_dump(bprm, bprm->file);
+ if (bprm->have_execfd)
+ would_dump(bprm, bprm->executable);
+
+ /*
+ * Figure out dumpability. Note that this checking only of current
+ * is wrong, but userspace depends on it. This should be testing
+ * bprm->secureexec instead.
+ */
+ if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP ||
+ is_dumpability_changed(current_cred(), bprm->cred) ||
+ !(uid_eq(current_euid(), current_uid()) &&
+ gid_eq(current_egid(), current_gid())))
+ set_dumpable(bprm->mm, suid_dumpable);
+ else
+ set_dumpable(bprm->mm, SUID_DUMP_USER);
+
/*
* Ensure all future errors are fatal.
*/
@@ -1261,7 +1304,7 @@ int begin_new_exec(struct linux_binprm * bprm)
/*
* Make this the only thread in the thread group.
*/
- retval = de_thread(me);
+ retval = de_thread(me, bprm);
if (retval)
goto out;
@@ -1284,11 +1327,6 @@ int begin_new_exec(struct linux_binprm * bprm)
if (retval)
goto out;
- /* If the binary is not readable then enforce mm->dumpable=0 */
- would_dump(bprm, bprm->file);
- if (bprm->have_execfd)
- would_dump(bprm, bprm->executable);
-
/*
* Release all of the old mmap stuff
*/
@@ -1350,18 +1388,6 @@ int begin_new_exec(struct linux_binprm * bprm)
me->sas_ss_sp = me->sas_ss_size = 0;
- /*
- * Figure out dumpability. Note that this checking only of current
- * is wrong, but userspace depends on it. This should be testing
- * bprm->secureexec instead.
- */
- if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP ||
- !(uid_eq(current_euid(), current_uid()) &&
- gid_eq(current_egid(), current_gid())))
- set_dumpable(current->mm, suid_dumpable);
- else
- set_dumpable(current->mm, SUID_DUMP_USER);
-
perf_event_exec();
__set_task_comm(me, kbasename(bprm->filename), true);
@@ -1480,6 +1506,11 @@ static int prepare_bprm_creds(struct linux_binprm *bprm)
if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex))
return -ERESTARTNOINTR;
+ if (unlikely(current->signal->exec_bprm)) {
+ mutex_unlock(¤t->signal->cred_guard_mutex);
+ return -ERESTARTNOINTR;
+ }
+
bprm->cred = prepare_exec_creds();
if (likely(bprm->cred))
return 0;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ffd54617c354..0da9adfadb48 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2788,6 +2788,12 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
if (rv < 0)
goto out_free;
+ if (unlikely(current->signal->exec_bprm)) {
+ mutex_unlock(¤t->signal->cred_guard_mutex);
+ rv = -ERESTARTNOINTR;
+ goto out_free;
+ }
+
rv = security_setprocattr(PROC_I(inode)->op.lsm,
file->f_path.dentry->d_name.name, page,
count);
diff --git a/include/linux/cred.h b/include/linux/cred.h
index f923528d5cc4..b01e309f5686 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -159,6 +159,7 @@ extern const struct cred *get_task_cred(struct task_struct *);
extern struct cred *cred_alloc_blank(void);
extern struct cred *prepare_creds(void);
extern struct cred *prepare_exec_creds(void);
+extern bool is_dumpability_changed(const struct cred *, const struct cred *);
extern int commit_creds(struct cred *);
extern void abort_creds(struct cred *);
extern const struct cred *override_creds(const struct cred *);
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 0014d3adaf84..14df7073a0a8 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -234,9 +234,27 @@ struct signal_struct {
struct mm_struct *oom_mm; /* recorded mm when the thread group got
* killed by the oom killer */
+ struct linux_binprm *exec_bprm; /* Used to check ptrace_may_access
+ * against new credentials while
+ * de_thread is waiting for other
+ * traced threads to terminate.
+ * Set while de_thread is executing.
+ * The cred_guard_mutex is released
+ * after de_thread() has called
+ * zap_other_threads(), therefore
+ * a fatal signal is guaranteed to be
+ * already pending in the unlikely
+ * event, that
+ * current->signal->exec_bprm happens
+ * to be non-zero after the
+ * cred_guard_mutex was acquired.
+ */
+
struct mutex cred_guard_mutex; /* guard against foreign influences on
* credential calculations
* (notably. ptrace)
+ * Held while execve runs, except when
+ * a sibling thread is being traced.
* Deprecated do not use in new code.
* Use exec_update_lock instead.
*/
diff --git a/kernel/cred.c b/kernel/cred.c
index 98cb4eca23fb..586cb6c7cf6b 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -433,6 +433,28 @@ static bool cred_cap_issubset(const struct cred *set, const struct cred *subset)
return false;
}
+/**
+ * is_dumpability_changed - Will changing creds from old to new
+ * affect the dumpability in commit_creds?
+ *
+ * Return: false - dumpability will not be changed in commit_creds.
+ * Return: true - dumpability will be changed to non-dumpable.
+ *
+ * @old: The old credentials
+ * @new: The new credentials
+ */
+bool is_dumpability_changed(const struct cred *old, const struct cred *new)
+{
+ if (!uid_eq(old->euid, new->euid) ||
+ !gid_eq(old->egid, new->egid) ||
+ !uid_eq(old->fsuid, new->fsuid) ||
+ !gid_eq(old->fsgid, new->fsgid) ||
+ !cred_cap_issubset(old, new))
+ return true;
+
+ return false;
+}
+
/**
* commit_creds - Install new credentials upon the current task
* @new: The credentials to be assigned
@@ -467,11 +489,7 @@ int commit_creds(struct cred *new)
get_cred(new); /* we will require a ref for the subj creds too */
/* dumpability changes */
- if (!uid_eq(old->euid, new->euid) ||
- !gid_eq(old->egid, new->egid) ||
- !uid_eq(old->fsuid, new->fsuid) ||
- !gid_eq(old->fsgid, new->fsgid) ||
- !cred_cap_issubset(old, new)) {
+ if (is_dumpability_changed(old, new)) {
if (task->mm)
set_dumpable(task->mm, suid_dumpable);
task->pdeath_signal = 0;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 443057bee87c..eb1c450bb7d7 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -20,6 +20,7 @@
#include <linux/pagemap.h>
#include <linux/ptrace.h>
#include <linux/security.h>
+#include <linux/binfmts.h>
#include <linux/signal.h>
#include <linux/uio.h>
#include <linux/audit.h>
@@ -435,6 +436,28 @@ static int ptrace_attach(struct task_struct *task, long request,
if (retval)
goto unlock_creds;
+ if (unlikely(task->in_execve)) {
+ struct linux_binprm *bprm = task->signal->exec_bprm;
+ const struct cred __rcu *old_cred;
+ struct mm_struct *old_mm;
+
+ retval = down_write_killable(&task->signal->exec_update_lock);
+ if (retval)
+ goto unlock_creds;
+ task_lock(task);
+ old_cred = task->real_cred;
+ old_mm = task->mm;
+ rcu_assign_pointer(task->real_cred, bprm->cred);
+ task->mm = bprm->mm;
+ retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
+ rcu_assign_pointer(task->real_cred, old_cred);
+ task->mm = old_mm;
+ task_unlock(task);
+ up_write(&task->signal->exec_update_lock);
+ if (retval)
+ goto unlock_creds;
+ }
+
write_lock_irq(&tasklist_lock);
retval = -EPERM;
if (unlikely(task->exit_state))
@@ -508,6 +531,14 @@ static int ptrace_traceme(void)
{
int ret = -EPERM;
+ if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex))
+ return -ERESTARTNOINTR;
+
+ if (unlikely(current->signal->exec_bprm)) {
+ mutex_unlock(¤t->signal->cred_guard_mutex);
+ return -ERESTARTNOINTR;
+ }
+
write_lock_irq(&tasklist_lock);
/* Are we already being traced? */
if (!current->ptrace) {
@@ -523,6 +554,7 @@ static int ptrace_traceme(void)
}
}
write_unlock_irq(&tasklist_lock);
+ mutex_unlock(¤t->signal->cred_guard_mutex);
return ret;
}
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 255999ba9190..b29bbfa0b044 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -1955,9 +1955,15 @@ static long seccomp_set_mode_filter(unsigned int flags,
* Make sure we cannot change seccomp or nnp state via TSYNC
* while another thread is in the middle of calling exec.
*/
- if (flags & SECCOMP_FILTER_FLAG_TSYNC &&
- mutex_lock_killable(¤t->signal->cred_guard_mutex))
- goto out_put_fd;
+ if (flags & SECCOMP_FILTER_FLAG_TSYNC) {
+ if (mutex_lock_killable(¤t->signal->cred_guard_mutex))
+ goto out_put_fd;
+
+ if (unlikely(current->signal->exec_bprm)) {
+ mutex_unlock(¤t->signal->cred_guard_mutex);
+ goto out_put_fd;
+ }
+ }
spin_lock_irq(¤t->sighand->siglock);
diff --git a/tools/testing/selftests/ptrace/vmaccess.c b/tools/testing/selftests/ptrace/vmaccess.c
index 4db327b44586..3b7d81fb99bb 100644
--- a/tools/testing/selftests/ptrace/vmaccess.c
+++ b/tools/testing/selftests/ptrace/vmaccess.c
@@ -39,8 +39,15 @@ TEST(vmaccess)
f = open(mm, O_RDONLY);
ASSERT_GE(f, 0);
close(f);
- f = kill(pid, SIGCONT);
- ASSERT_EQ(f, 0);
+ f = waitpid(-1, NULL, 0);
+ ASSERT_NE(f, -1);
+ ASSERT_NE(f, 0);
+ ASSERT_NE(f, pid);
+ f = waitpid(-1, NULL, 0);
+ ASSERT_EQ(f, pid);
+ f = waitpid(-1, NULL, 0);
+ ASSERT_EQ(f, -1);
+ ASSERT_EQ(errno, ECHILD);
}
TEST(attach)
@@ -57,22 +64,24 @@ TEST(attach)
sleep(1);
k = ptrace(PTRACE_ATTACH, pid, 0L, 0L);
- ASSERT_EQ(errno, EAGAIN);
- ASSERT_EQ(k, -1);
+ ASSERT_EQ(k, 0);
k = waitpid(-1, &s, WNOHANG);
ASSERT_NE(k, -1);
ASSERT_NE(k, 0);
ASSERT_NE(k, pid);
ASSERT_EQ(WIFEXITED(s), 1);
ASSERT_EQ(WEXITSTATUS(s), 0);
- sleep(1);
- k = ptrace(PTRACE_ATTACH, pid, 0L, 0L);
+ k = waitpid(-1, &s, 0);
+ ASSERT_EQ(k, pid);
+ ASSERT_EQ(WIFSTOPPED(s), 1);
+ ASSERT_EQ(WSTOPSIG(s), SIGTRAP);
+ k = ptrace(PTRACE_CONT, pid, 0L, 0L);
ASSERT_EQ(k, 0);
k = waitpid(-1, &s, 0);
ASSERT_EQ(k, pid);
ASSERT_EQ(WIFSTOPPED(s), 1);
ASSERT_EQ(WSTOPSIG(s), SIGSTOP);
- k = ptrace(PTRACE_DETACH, pid, 0L, 0L);
+ k = ptrace(PTRACE_CONT, pid, 0L, 0L);
ASSERT_EQ(k, 0);
k = waitpid(-1, &s, 0);
ASSERT_EQ(k, pid);
--
2.39.2
Make sv48 the default address space for mmap as some applications
currently depend on this assumption. Users can now select a
desired address space using a non-zero hint address to mmap. Previously,
requesting the default address space from mmap by passing zero as the hint
address would result in using the largest address space possible. Some
applications depend on empty bits in the virtual address space, like Go and
Java, so this patch provides more flexibility for application developers.
-Charlie
---
v10:
- Move pgtable.h defintions into a no __ASSEMBLY__ region to resolve compilation
conflicts (pointed out by Conor)
- Will now compile with allmodconfig
v9:
- Raise the mmap_end default to STACK_TOP_MAX to allow the address space to grow
beyond the default of sv48 on sv57 machines as suggested by Alexandre
- Some of the mmap macros had unnecessary conditionals that I have removed
v8:
- Fix RV32 and the RV32 compat mode of RV64 (suggested by Conor)
- Extract out addr and base from the mmap macros (suggested by Alexandre)
v7:
- Changing RLIMIT_STACK inside of an executing program does not trigger
arch_pick_mmap_layout(), so rewrite tests to change RLIMIT_STACK from a
script before executing tests. RLIMIT_STACK of infinity forces bottomup
mmap allocation.
- Make arch_get_mmap_base macro more readible by extracting out the rnd
calculation.
- Use MMAP_MIN_VA_BITS in TASK_UNMAPPED_BASE to support case when mmap
attempts to allocate address smaller than DEFAULT_MAP_WINDOW.
- Fix incorrect wording in documentation.
v6:
- Rebase onto the correct base
v5:
- Minor wording change in documentation
- Change some parenthesis in arch_get_mmap_ macros
- Added case for addr==0 in arch_get_mmap_ because without this, programs would
crash if RLIMIT_STACK was modified before executing the program. This was
tested using the libhugetlbfs tests.
v4:
- Split testcases/document patch into test cases, in-code documentation, and
formal documentation patches
- Modified the mmap_base macro to be more legible and better represent memory
layout
- Fixed documentation to better reflect the implmentation
- Renamed DEFAULT_VA_BITS to MMAP_VA_BITS
- Added additional test case for rlimit changes
---
Charlie Jenkins (4):
RISC-V: mm: Restrict address space for sv39,sv48,sv57
RISC-V: mm: Add tests for RISC-V mm
RISC-V: mm: Update pgtable comment documentation
RISC-V: mm: Document mmap changes
Documentation/riscv/vm-layout.rst | 22 +++++++
arch/riscv/include/asm/elf.h | 2 +-
arch/riscv/include/asm/pgtable.h | 33 ++++++++--
arch/riscv/include/asm/processor.h | 52 +++++++++++++--
tools/testing/selftests/riscv/Makefile | 2 +-
tools/testing/selftests/riscv/mm/.gitignore | 2 +
tools/testing/selftests/riscv/mm/Makefile | 15 +++++
.../riscv/mm/testcases/mmap_bottomup.c | 35 ++++++++++
.../riscv/mm/testcases/mmap_default.c | 35 ++++++++++
.../selftests/riscv/mm/testcases/mmap_test.h | 64 +++++++++++++++++++
.../selftests/riscv/mm/testcases/run_mmap.sh | 12 ++++
11 files changed, 261 insertions(+), 13 deletions(-)
create mode 100644 tools/testing/selftests/riscv/mm/.gitignore
create mode 100644 tools/testing/selftests/riscv/mm/Makefile
create mode 100644 tools/testing/selftests/riscv/mm/testcases/mmap_bottomup.c
create mode 100644 tools/testing/selftests/riscv/mm/testcases/mmap_default.c
create mode 100644 tools/testing/selftests/riscv/mm/testcases/mmap_test.h
create mode 100755 tools/testing/selftests/riscv/mm/testcases/run_mmap.sh
--
2.34.1