From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 608433F2109; Wed, 5 Aug 2026 21:27:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785965240; cv=none; b=QvuIcTBIb03W0HgRjB0RW5uj86K1qs130VyGX+d43taOeU7Dnumd4PVgveaBXIJb7CqudsvIHGLnKiGPkUEWwUPnVidOTHnBdAmsLmCic6ZGD+tuz/056ScdKildf1IQ5kKm9y+hcfiEQrd0O+qCC6op8ypEoWOMFVk6JV0yAp8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785965240; c=relaxed/simple; bh=p1S8g7m1+MhoK7RRb87ukE8btgQpT7Hp/ZdsQZAHicE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GeCwDLT2PT995506jqQq5hphYcQyeP2tklxTD/LQCblKiJdsLkDYQHJba6Ouppo2kS1LQf6R6MbxJEw7uXVquIKYP6hALQ9R7Gk7OwbHhfVun8yyqwTJjLdsiYjzhA97cQ0HKN4V5x6FkNZk4fjJC6uYWyOgYOGlTJnvvwnj6fQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C9J9mR9z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="C9J9mR9z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32D9C1F00A3A; Wed, 5 Aug 2026 21:27:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785965239; bh=L+XgG3zRC2xuZyKC3GoSym/L/+7SSWd9pP/277f7PNg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=C9J9mR9ziHAYCLDcrxZBKit7lNIwCbdlYSdAI8FCcVB+D/pJqhd++2NS0scsKc0Ql OHai3I93zpgy2tlIWpiAogcBMNcrbMMxIcInxbQnk1BKnUIi4dZ5c4/nYU6NLvBNm/ UxjEf6QRd3zv+hgYuK5CWCU8uPK90Dgb5xgqU2l/1c4s+pwa3liqpqyq9mtsI36lLM D4il3aqm5PqETqwDSyy3NzrstDiIPJi29SqcWE4ayiBjjccxFXnIoXts1BmgzMAOGN 7rsyhYr4TRqDblPqIuUKrywBrUMGUswoRl/pEOl7hUb9A8xrve1j1kNiiDoAAKQkRQ f25MUOJaprRsw== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , Stephane Eranian Subject: [PATCH 01/12] perf jitdump: Fix extended header read that always fails Date: Wed, 5 Aug 2026 18:26:51 -0300 Message-ID: <20260805212704.267779-2-acme@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260805212704.267779-1-acme@kernel.org> References: <20260805212704.267779-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo jit_open() sets bsz = bs before the fread() that uses bs - bsz as the read size, making the expression always evaluate to zero. fread() with size 0 returns 0, which triggers the ret != 1 error path — so extended jitdump headers (total_size > sizeof(header)) have been silently broken since the original implementation. Additionally, when 0 < bs <= bsz the if (bs > bsz) block is skipped entirely, leaving extended header bytes unread in the stream. Subsequent jit_get_next_entry() calls then parse those leftover bytes as a jr_prefix, corrupting the record stream. Fix by separating the buffer growth from the read: realloc only when bs > bsz, then unconditionally fread bs bytes when bs > 0. Fixes: 9b07e27f88b9cd78 ("perf inject: Add jitdump mmap injection support") Reported-by: sashiko-bot Cc: Stephane Eranian Cc: Ian Rogers Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6 Reviewed-by: Ian Rogers Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/jitdump.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c index 83005b30b9bf3fd7..4b7c7ba7cd95ddbb 100644 --- a/tools/perf/util/jitdump.c +++ b/tools/perf/util/jitdump.c @@ -224,10 +224,12 @@ jit_open(struct jit_buf_desc *jd, const char *name) n = realloc(buf, bs); if (!n) goto error; - bsz = bs; buf = n; - /* read extra we do not know about */ - ret = fread(buf, bs - bsz, 1, jd->in); + bsz = bs; + } + if (bs > 0) { + /* consume extended header bytes from the stream */ + ret = fread(buf, bs, 1, jd->in); if (ret != 1) goto error; } -- 2.55.0