From patchwork Wed Feb 5 22:50:35 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13961991 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8D28621A450; Wed, 5 Feb 2025 22:50:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738795823; cv=none; b=koBt5ay5hYEWFKgvfH05lmHRdJAFE41S334+78VaxjrCA6aWsRI1YO3orz+PVaaGHEd8wFPHw0oMv2p/U9z3rhTZsX6HYSYuozHj8LJ/5sFk36v4MOBMcom14dhsqWEf01PZDm6HEvk0RAMWkC7jU+gHe57DUtGWv3IQDUjGVLU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738795823; c=relaxed/simple; bh=KzEsDQvkXIUiOxDlG2zAYbasAvlRkiTu3GNzggoIWGQ=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=iKOkTsdERRRx1hfH4OaA/RUeLjBO15f5ix2ioUHuJC2dl7osItkUAZaRs6FOgbzERckunluCs/vIenvYRLqJ7G7EaczKzYdRQKeahWBaBLxQC1d9iGD0Oa5ajFhxXhBRTRSdcWyQ6WTpQEqx0akgSe4f1/mw6W/b9GPNr/zcnjA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 360B4C4CEE7; Wed, 5 Feb 2025 22:50:23 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1tfoEZ-00000007gV7-36cq; Wed, 05 Feb 2025 17:51:03 -0500 Message-ID: <20250205225103.596907199@goodmis.org> User-Agent: quilt/0.68 Date: Wed, 05 Feb 2025 17:50:35 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [PATCH 4/8] tracing: Have persistent trace instances save KASLR offset References: <20250205225031.799739376@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Steven Rostedt There's no reason to save the KASLR offset for the ring buffer itself. That is used by the tracer. Now that the tracer has a way to save data in the persistent memory of the ring buffer, have the tracing infrastructure take care of the saving of the KASLR offset. Signed-off-by: Steven Rostedt (Google) --- include/linux/ring_buffer.h | 1 - kernel/trace/ring_buffer.c | 47 ------------------------------------- kernel/trace/trace.c | 38 ++++++++++++++++++++++++++---- kernel/trace/trace.h | 6 +++-- 4 files changed, 38 insertions(+), 54 deletions(-) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index b95f940fd07a..d6d9c94e8d8a 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -94,7 +94,6 @@ struct trace_buffer *__ring_buffer_alloc_range(unsigned long size, unsigned flag unsigned long range_size, struct lock_class_key *key); -bool ring_buffer_last_boot_delta(struct trace_buffer *buffer, unsigned long *kaslr_addr); void *ring_buffer_meta_scratch(struct trace_buffer *buffer, unsigned int *size); /* diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 5a81ff785665..a42406287281 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -55,7 +55,6 @@ struct ring_buffer_meta { }; struct ring_buffer_cpu_meta { - unsigned long kaslr_addr; unsigned long first_buffer; unsigned long head_buffer; unsigned long commit_buffer; @@ -557,8 +556,6 @@ struct trace_buffer { struct ring_buffer_meta *meta; - unsigned long kaslr_addr; - unsigned int subbuf_size; unsigned int subbuf_order; unsigned int max_data_size; @@ -1931,15 +1928,6 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) } } -static void rb_meta_init_text_addr(struct ring_buffer_cpu_meta *meta) -{ -#ifdef CONFIG_RANDOMIZE_BASE - meta->kaslr_addr = kaslr_offset(); -#else - meta->kaslr_addr = 0; -#endif -} - static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages) { struct ring_buffer_cpu_meta *meta; @@ -1967,7 +1955,6 @@ static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages) meta->first_buffer += delta; meta->head_buffer += delta; meta->commit_buffer += delta; - buffer->kaslr_addr = meta->kaslr_addr; continue; } @@ -1984,7 +1971,6 @@ static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages) subbuf = rb_subbufs_from_meta(meta); meta->first_buffer = (unsigned long)subbuf; - rb_meta_init_text_addr(meta); /* * The buffers[] array holds the order of the sub-buffers @@ -2514,27 +2500,6 @@ struct trace_buffer *__ring_buffer_alloc_range(unsigned long size, unsigned flag return alloc_buffer(size, flags, order, start, start + range_size, key); } -/** - * ring_buffer_last_boot_delta - return the delta offset from last boot - * @buffer: The buffer to return the delta from - * @text: Return text delta - * @data: Return data delta - * - * Returns: The true if the delta is non zero - */ -bool ring_buffer_last_boot_delta(struct trace_buffer *buffer, unsigned long *kaslr_addr) -{ - if (!buffer) - return false; - - if (!buffer->kaslr_addr) - return false; - - *kaslr_addr = buffer->kaslr_addr; - - return true; -} - void *ring_buffer_meta_scratch(struct trace_buffer *buffer, unsigned int *size) { if (!buffer || !buffer->meta) @@ -6098,7 +6063,6 @@ static void reset_disabled_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer) void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu) { struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu]; - struct ring_buffer_cpu_meta *meta; if (!cpumask_test_cpu(cpu, buffer->cpumask)) return; @@ -6117,11 +6081,6 @@ void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu) atomic_dec(&cpu_buffer->record_disabled); atomic_dec(&cpu_buffer->resize_disabled); - /* Make sure persistent meta now uses this buffer's addresses */ - meta = rb_range_meta(buffer, 0, cpu_buffer->cpu); - if (meta) - rb_meta_init_text_addr(meta); - mutex_unlock(&buffer->mutex); } EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu); @@ -6136,7 +6095,6 @@ EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu); void ring_buffer_reset_online_cpus(struct trace_buffer *buffer) { struct ring_buffer_per_cpu *cpu_buffer; - struct ring_buffer_cpu_meta *meta; int cpu; /* prevent another thread from changing buffer sizes */ @@ -6164,11 +6122,6 @@ void ring_buffer_reset_online_cpus(struct trace_buffer *buffer) reset_disabled_cpu_buffer(cpu_buffer); - /* Make sure persistent meta now uses this buffer's addresses */ - meta = rb_range_meta(buffer, 0, cpu_buffer->cpu); - if (meta) - rb_meta_init_text_addr(meta); - atomic_dec(&cpu_buffer->record_disabled); atomic_sub(RESET_BIT, &cpu_buffer->resize_disabled); } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a9e8eaf1d47e..cb9f8e6878a0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5994,8 +5994,14 @@ ssize_t tracing_resize_ring_buffer(struct trace_array *tr, return ret; } +struct trace_scratch { + unsigned long kaslr_addr; +}; + static void update_last_data(struct trace_array *tr) { + struct trace_scratch *tscratch; + if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) return; @@ -6010,6 +6016,17 @@ static void update_last_data(struct trace_array *tr) /* Using current data now */ tr->text_delta = 0; + if (!tr->scratch) + return; + + tscratch = tr->scratch; + + /* Set the persistent ring buffer meta data to this address */ +#ifdef CONFIG_RANDOMIZE_BASE + tscratch->kaslr_addr = kaslr_offset(); +#else + tscratch->kaslr_addr = 0; +#endif tr->flags &= ~TRACE_ARRAY_FL_LAST_BOOT; } @@ -6823,6 +6840,7 @@ static ssize_t tracing_last_boot_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; + struct trace_scratch *tscratch = tr->scratch; struct seq_buf seq; char buf[64]; @@ -6835,10 +6853,10 @@ tracing_last_boot_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t * Otherwise it shows the KASLR address from the previous boot which * should not be the same as the current boot. */ - if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) + if (!tscratch || !(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) seq_buf_puts(&seq, "Offset: current\n"); else - seq_buf_printf(&seq, "Offset: %lx\n", tr->kaslr_addr); + seq_buf_printf(&seq, "Offset: %lx\n", tscratch->kaslr_addr); return simple_read_from_buffer(ubuf, cnt, ppos, buf, seq_buf_used(&seq)); } @@ -9212,6 +9230,8 @@ static int allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size) { enum ring_buffer_flags rb_flags; + unsigned int scratch_size; + void *scratch; rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0; @@ -9222,10 +9242,20 @@ allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size tr->range_addr_start, tr->range_addr_size); + scratch = ring_buffer_meta_scratch(buf->buffer, &scratch_size); + if (scratch) { + tr->scratch = scratch; + tr->scratch_size = scratch_size; + #ifdef CONFIG_RANDOMIZE_BASE - if (ring_buffer_last_boot_delta(buf->buffer, &tr->kaslr_addr)) - tr->text_delta = kaslr_offset() - tr->kaslr_addr; + { + struct trace_scratch *tscratch = tr->scratch; + + if (tscratch->kaslr_addr) + tr->text_delta = kaslr_offset() - tscratch->kaslr_addr; + } #endif + } /* * This is basically the same as a mapped buffer, * with the same restrictions. diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index abe8169c3e87..3a020fb82a34 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -348,8 +348,11 @@ struct trace_array { unsigned int mapped; unsigned long range_addr_start; unsigned long range_addr_size; - unsigned long kaslr_addr; long text_delta; + void *scratch; /* pointer in persistent memory */ + int scratch_size; + + int buffer_disabled; struct trace_pid_list __rcu *filtered_pids; struct trace_pid_list __rcu *filtered_no_pids; @@ -367,7 +370,6 @@ struct trace_array { * CONFIG_TRACER_MAX_TRACE. */ arch_spinlock_t max_lock; - int buffer_disabled; #ifdef CONFIG_FTRACE_SYSCALLS int sys_refcount_enter; int sys_refcount_exit;