mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-28 14:34:17 -04:00
Code Issues Packages Projects Releases Wiki Activity

selftests/mm: fix clone cleartid race in pkey sighandler tests

Browse Source 
Passing a stack-local child_pid to clone() with CLONE_CHILD_CLEARTID is
unsafe: the kernel clears that address when the child exits, which may
happen after the test function has returned and the stack slot has been
reused.

Neither testcase uses the settid/cleartid pointers for synchronization.

Drop CLONE_PARENT_SETTID and CLONE_CHILD_CLEARTID and pass NULL for the
clone tid arguments.  Wait for the clone child to exit via tkill in
test_sigsegv_handler_with_different_pkey_for_stack(), matching
test_pkru_sigreturn(), so the detached thread cannot overlap with the next
testcase.

Link: https://lore.kernel.org/20260706081600.3570203-7-lihongfu@kylinos.cn
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Cc: David Hildenbrand <david@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Keith Lucas <keith.lucas@oracle.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Yury Khrustalev <yury.khrustalev@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Hongfu Li
2026-07-06 16:16:00 +08:00
committed by Andrew Morton
parent 5a8e068339
commit c5efd0bded
1 changed files with 12 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
tools/testing/selftests/mm/pkey_sighandler_tests.c
View File

@@ -290,7 +290,6 @@ static void test_sigsegv_handler_with_different_pkey_for_stack(void)
static stack_t sigstack;
void *stack;
int pkey;
int parent_pid = 0;
int child_pid = 0;
u64 pkey_reg;
long ret;
@@ -330,11 +329,10 @@ static void test_sigsegv_handler_with_different_pkey_for_stack(void)
/* Use clone to avoid newer glibcs using rseq on new threads */
ret = clone_raw(CLONE_VM | CLONE_FS | CLONE_FILES |
CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM |
CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID |
CLONE_DETACHED,
stack + STACK_SIZE,
&parent_pid,
&child_pid);
NULL,
NULL);
if (ret < 0) {
errno = -ret;
@@ -344,11 +342,19 @@ static void test_sigsegv_handler_with_different_pkey_for_stack(void)
syscall_raw(SYS_exit, 0, 0, 0, 0, 0, 0);
}
child_pid = ret;
pthread_mutex_lock(&mutex);
while (siginfo.si_signo == 0)
pthread_cond_wait(&cond, &mutex);
pthread_mutex_unlock(&mutex);
/* Wait for child to exit before returning */
do {
sched_yield();
ret = syscall_raw(SYS_tkill, child_pid, 0, 0, 0, 0, 0);
} while (ret != -ESRCH && ret != -EINVAL);
ksft_test_result(siginfo.si_signo == SIGSEGV &&
siginfo.si_code == SEGV_MAPERR &&
siginfo.si_addr == NULL,
@@ -445,7 +451,6 @@ static void test_pkru_sigreturn(void)
static stack_t sigstack;
void *stack;
int pkey;
int parent_pid = 0;
int child_pid = 0;
u64 pkey_reg;
long ret;
@@ -504,11 +509,10 @@ static void test_pkru_sigreturn(void)
/* Use clone to avoid newer glibcs using rseq on new threads */
ret = clone_raw(CLONE_VM | CLONE_FS | CLONE_FILES |
CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM |
CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID |
CLONE_DETACHED,
stack + STACK_SIZE,
&parent_pid,
&child_pid);
NULL,
NULL);
if (ret < 0) {
errno = -ret;