From: Jiri Olsa <jolsa@kernel.org> mainline inclusion from mainline-v7.3-rc1 commit f5d242825ca417bb6afe35fde6e8880f97ca43fb category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18560 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Both bpf_get_task_stack and bpf_get_task_stack_sleepable helpers that use __bpf_get_task_stack have buf defined as ARG_PTR_TO_UNINIT_MEM argument and we should initialize the buf on every return path. Adding missing buf memset for __bpf_get_task_stack fail paths. This provides deterministic buffer contents, which is useful when the buffer is used directly as a map key. Fixes: 06ab134ce8ec ("bpf: Refcount task stack in bpf_get_task_stack") Fixes: b992f01e6615 ("bpf: Guard against accessing NULL pt_regs in bpf_get_task_stack()") Reported-by: Sashiko <sashiko-bot@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260803210149.296496-10-jolsa@kernel.org Conflicts: kernel/bpf/stackmap.c [commit 58cfc2201d964163fe9c4a703136eb64db799f08 not backport] Signed-off-by: Chen Yuxi <chenyuxi19@huawei.com> --- kernel/bpf/stackmap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 7f8adb1dc152..2a4070d0b594 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -501,14 +501,17 @@ BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf, struct pt_regs *regs; long res = -EINVAL; - if (!try_get_task_stack(task)) + if (!try_get_task_stack(task)) { + memset(buf, 0, size); return -EFAULT; + } regs = task_pt_regs(task); if (regs) res = __bpf_get_stack(regs, task, NULL, buf, size, flags); + else + memset(buf, 0, size); put_task_stack(task); - return res; } -- 2.34.1