From db9108e054700c96322b0f0028546aa4e643cf0b Mon Sep 17 00:00:00 2001 From: Chunyu Hu Date: Thu, 20 Jul 2017 18:36:09 +0800 Subject: tracing: Fix kmemleak in instance_rmdir Hit the kmemleak when executing instance_rmdir, it forgot releasing mem of tracing_cpumask. With this fix, the warn does not appear any more. unreferenced object 0xffff93a8dfaa7c18 (size 8): comm "mkdir", pid 1436, jiffies 4294763622 (age 9134.308s) hex dump (first 8 bytes): ff ff ff ff ff ff ff ff ........ backtrace: [] kmemleak_alloc+0x4a/0xa0 [] __kmalloc_node+0xf1/0x280 [] alloc_cpumask_var_node+0x23/0x30 [] alloc_cpumask_var+0xe/0x10 [] instance_mkdir+0x90/0x240 [] tracefs_syscall_mkdir+0x40/0x70 [] vfs_mkdir+0x109/0x1b0 [] SyS_mkdir+0xd0/0x100 [] do_syscall_64+0x67/0x150 [] return_from_SYSCALL_64+0x0/0x6a [] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1500546969-12594-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: ccfe9e42e451 ("tracing: Make tracing_cpumask available for all instances") Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2d0ffcc49dba..42b9355033d4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7774,6 +7774,7 @@ static int instance_rmdir(const char *name) } kfree(tr->topts); + free_cpumask_var(tr->tracing_cpumask); kfree(tr->name); kfree(tr); -- cgit v1.2.3 From 4bb0f0e73c8c30917d169c4a0f1ac083690c545b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 1 Aug 2017 12:01:52 -0400 Subject: tracing: Call clear_boot_tracer() at lateinit_sync The clear_boot_tracer function is used to reset the default_bootup_tracer string to prevent it from being accessed after boot, as it originally points to init data. But since clear_boot_tracer() is called via the init_lateinit() call, it races with the initcall for registering the hwlat tracer. If someone adds "ftrace=hwlat" to the kernel command line, depending on how the linker sets up the text, the saved command line may be cleared, and the hwlat tracer never is initialized. Simply have the clear_boot_tracer() be called by initcall_lateinit_sync() as that's for tasks to be called after lateinit. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196551 Cc: stable@vger.kernel.org Fixes: e7c15cd8a ("tracing: Added hardware latency tracer") Reported-by: Zamir SUN Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 42b9355033d4..784fb43b2abe 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8407,4 +8407,4 @@ __init static int clear_boot_tracer(void) } fs_initcall(tracer_init_tracefs); -late_initcall(clear_boot_tracer); +late_initcall_sync(clear_boot_tracer); -- cgit v1.2.3 From 147d88e0b5eb90191bc5c12ca0a3c410b75a13d2 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 1 Aug 2017 14:02:01 +0300 Subject: tracing: Missing error code in tracer_alloc_buffers() If ring_buffer_alloc() or one of the next couple function calls fail then we should return -ENOMEM but the current code returns success. Link: http://lkml.kernel.org/r/20170801110201.ajdkct7vwzixahvx@mwanda Cc: Sebastian Andrzej Siewior Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: b32614c03413 ('tracing/rb: Convert to hotplug state machine') Signed-off-by: Dan Carpenter Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 784fb43b2abe..d815fc317e9d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8293,6 +8293,7 @@ __init static int tracer_alloc_buffers(void) if (ret < 0) goto out_free_cpumask; /* Used for event triggers */ + ret = -ENOMEM; temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE); if (!temp_buffer) goto out_rm_hp_state; -- cgit v1.2.3 From a7e52ad7ed82e21273eccff93d1477a7b313aabb Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 2 Aug 2017 14:20:54 -0400 Subject: ring-buffer: Have ring_buffer_alloc_read_page() return error on offline CPU Chunyu Hu reported: "per_cpu trace directories and files are created for all possible cpus, but only the cpus which have ever been on-lined have their own per cpu ring buffer (allocated by cpuhp threads). While trace_buffers_open, the open handler for trace file 'trace_pipe_raw' is always trying to access field of ring_buffer_per_cpu, and would panic with the NULL pointer. Align the behavior of trace_pipe_raw with trace_pipe, that returns -NODEV when openning it if that cpu does not have trace ring buffer. Reproduce: cat /sys/kernel/debug/tracing/per_cpu/cpu31/trace_pipe_raw (cpu31 is never on-lined, this is a 16 cores x86_64 box) Tested with: 1) boot with maxcpus=14, read trace_pipe_raw of cpu15. Got -NODEV. 2) oneline cpu15, read trace_pipe_raw of cpu15. Get the raw trace data. Call trace: [ 5760.950995] RIP: 0010:ring_buffer_alloc_read_page+0x32/0xe0 [ 5760.961678] tracing_buffers_read+0x1f6/0x230 [ 5760.962695] __vfs_read+0x37/0x160 [ 5760.963498] ? __vfs_read+0x5/0x160 [ 5760.964339] ? security_file_permission+0x9d/0xc0 [ 5760.965451] ? __vfs_read+0x5/0x160 [ 5760.966280] vfs_read+0x8c/0x130 [ 5760.967070] SyS_read+0x55/0xc0 [ 5760.967779] do_syscall_64+0x67/0x150 [ 5760.968687] entry_SYSCALL64_slow_path+0x25/0x25" This was introduced by the addition of the feature to reuse reader pages instead of re-allocating them. The problem is that the allocation of a reader page (which is per cpu) does not check if the cpu is online and set up for the ring buffer. Link: http://lkml.kernel.org/r/1500880866-1177-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 73a757e63114 ("ring-buffer: Return reader page back into existing ring buffer") Reported-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 14 +++++++++----- kernel/trace/ring_buffer_benchmark.c | 2 +- kernel/trace/trace.c | 16 +++++++++++----- 3 files changed, 21 insertions(+), 11 deletions(-) (limited to 'kernel/trace/trace.c') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 529cc50d7243..81279c6602ff 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -4386,15 +4386,19 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu); * the page that was allocated, with the read page of the buffer. * * Returns: - * The page allocated, or NULL on error. + * The page allocated, or ERR_PTR */ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu) { - struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu]; + struct ring_buffer_per_cpu *cpu_buffer; struct buffer_data_page *bpage = NULL; unsigned long flags; struct page *page; + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return ERR_PTR(-ENODEV); + + cpu_buffer = buffer->buffers[cpu]; local_irq_save(flags); arch_spin_lock(&cpu_buffer->lock); @@ -4412,7 +4416,7 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu) page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_NORETRY, 0); if (!page) - return NULL; + return ERR_PTR(-ENOMEM); bpage = page_address(page); @@ -4467,8 +4471,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_free_read_page); * * for example: * rpage = ring_buffer_alloc_read_page(buffer, cpu); - * if (!rpage) - * return error; + * if (IS_ERR(rpage)) + * return PTR_ERR(rpage); * ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0); * if (ret >= 0) * process_page(rpage, ret); diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index 9fbcaf567886..68ee79afe31c 100644 --- a/kernel/trace/ring_buffer_benchmark.c +++ b/kernel/trace/ring_buffer_benchmark.c @@ -113,7 +113,7 @@ static enum event_status read_page(int cpu) int i; bpage = ring_buffer_alloc_read_page(buffer, cpu); - if (!bpage) + if (IS_ERR(bpage)) return EVENT_DROPPED; ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d815fc317e9d..44004d8aa3b3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6598,7 +6598,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, { struct ftrace_buffer_info *info = filp->private_data; struct trace_iterator *iter = &info->iter; - ssize_t ret; + ssize_t ret = 0; ssize_t size; if (!count) @@ -6612,10 +6612,15 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, if (!info->spare) { info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer, iter->cpu_file); - info->spare_cpu = iter->cpu_file; + if (IS_ERR(info->spare)) { + ret = PTR_ERR(info->spare); + info->spare = NULL; + } else { + info->spare_cpu = iter->cpu_file; + } } if (!info->spare) - return -ENOMEM; + return ret; /* Do we have previous read data to read? */ if (info->read < PAGE_SIZE) @@ -6790,8 +6795,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, ref->ref = 1; ref->buffer = iter->trace_buffer->buffer; ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file); - if (!ref->page) { - ret = -ENOMEM; + if (IS_ERR(ref->page)) { + ret = PTR_ERR(ref->page); + ref->page = NULL; kfree(ref); break; } -- cgit v1.2.3