From: Ravi Bangoria <ravi.bangoria@amd.com> mainline inclusion from mainline-v7.1-rc1 commit b0a09142622a994c4f4088c3f61db5da87cfc711 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15810 CVE: CVE-2026-53114 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ---------------------------------------------------------------------- Calling perf_allow_kernel() from the NMI context is unsafe and could be fatal. Capture the permission at event-initialization time by storing it in event->hw.flags, and have the NMI handler rely on that cached flag instead of making the call directly. Fixes: 50a53b60e141 ("perf/amd/ibs: Prevent leaking sensitive data to userspace") Reported-by: Sadasivan Shaiju <sadasivan.shaiju2@amd.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Link: https://patch.msgid.link/20260216042216.1440-5-ravi.bangoria@amd.com Conflicts: arch/x86/events/amd/ibs.c [Fix conflict because commit 9ec84f79c5a7 is not merged.] Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- arch/x86/events/amd/ibs.c | 5 ++++- arch/x86/events/perf_event_flags.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c index c775047a1bda..74b0c608af5d 100644 --- a/arch/x86/events/amd/ibs.c +++ b/arch/x86/events/amd/ibs.c @@ -312,6 +312,9 @@ static int perf_ibs_init(struct perf_event *event) if (ret) return ret; + if (perf_allow_kernel(&event->attr)) + hwc->flags |= PERF_X86_EVENT_UNPRIVILEGED; + if (hwc->sample_period) { if (config & perf_ibs->cnt_mask) /* raw max_cnt may not be set */ @@ -1343,7 +1346,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs) * unprivileged users. */ if ((event->attr.sample_type & PERF_SAMPLE_RAW) && - perf_allow_kernel(&event->attr)) { + (hwc->flags & PERF_X86_EVENT_UNPRIVILEGED)) { perf_ibs_phyaddr_clear(perf_ibs, &ibs_data); } diff --git a/arch/x86/events/perf_event_flags.h b/arch/x86/events/perf_event_flags.h index 70078334e4a3..47f84ee8f540 100644 --- a/arch/x86/events/perf_event_flags.h +++ b/arch/x86/events/perf_event_flags.h @@ -23,3 +23,4 @@ PERF_ARCH(PEBS_LAT_HYBRID, 0x0020000) /* ld and st lat for hybrid */ PERF_ARCH(NEEDS_BRANCH_STACK, 0x0040000) /* require branch stack setup */ PERF_ARCH(BRANCH_COUNTERS, 0x0080000) /* logs the counters in the extra space of each branch */ PERF_ARCH(ACR, 0x0100000) /* Auto counter reload */ +PERF_ARCH(UNPRIVILEGED, 0x0200000) /* Unprivileged event (wrt perf_allow_kernel()) */ -- 2.34.1