5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo [ Upstream commit cc6abe0012bf8c04af8275266f8ed7c55ba4a5fb ] The guestmount path is built with snprintf() into a PATH_MAX buffer without checking the return value. If symbol_conf.guestmount is long enough to cause truncation, the truncated path could match a different directory, causing the wrong guest to be associated with the pid. Check for truncation and bail out early. Fixes: a1645ce12adb ("perf: 'perf kvm' tool for monitoring guest performance from host") Reported-by: sashiko-bot Cc: Zhang, Yanmin Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin --- tools/perf/util/machine.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 4907459639b6f..be18fd39813f6 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -347,7 +347,12 @@ struct machine *machines__findnew(struct machines *machines, pid_t pid) if ((pid != HOST_KERNEL_ID) && (pid != DEFAULT_GUEST_KERNEL_ID) && (symbol_conf.guestmount)) { - snprintf(path, sizeof(path), "%s/%d", symbol_conf.guestmount, pid); + if (snprintf(path, sizeof(path), "%s/%d", + symbol_conf.guestmount, pid) >= (int)sizeof(path)) { + pr_err("Guest path too long for pid %d\n", pid); + machine = NULL; + goto out; + } if (access(path, R_OK)) { static struct strlist *seen; -- 2.53.0