From db08d2cf82389b06a04c4b9b6582299a77983ae8 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 30 Sep 2023 12:30:38 +0000 Subject: [PATCH] Revert "tracing: Introduce pipe_cpumask to avoid race on trace_pipes" This reverts commit 0c0547d2a60aa1d5bd9edb7f14e167d081875eba which is commit c2489bb7e6be2e8cdced12c16c42fa128403ac03 upstream. It breaks the Android kabi and is not needed for Android systems. If it is needed in the future, it can be brought back in an abi-safe way. Bug: 161946584 Change-Id: I014d4486d85641031f816da38b00c593dcb8eae6 Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 55 ++++++-------------------------------------- kernel/trace/trace.h | 2 -- 2 files changed, 7 insertions(+), 50 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7ae5002cf5a4..34287d0a5e86 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6189,36 +6189,10 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf, #endif -static int open_pipe_on_cpu(struct trace_array *tr, int cpu) -{ - if (cpu == RING_BUFFER_ALL_CPUS) { - if (cpumask_empty(tr->pipe_cpumask)) { - cpumask_setall(tr->pipe_cpumask); - return 0; - } - } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) { - cpumask_set_cpu(cpu, tr->pipe_cpumask); - return 0; - } - return -EBUSY; -} - -static void close_pipe_on_cpu(struct trace_array *tr, int cpu) -{ - if (cpu == RING_BUFFER_ALL_CPUS) { - WARN_ON(!cpumask_full(tr->pipe_cpumask)); - cpumask_clear(tr->pipe_cpumask); - } else { - WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask)); - cpumask_clear_cpu(cpu, tr->pipe_cpumask); - } -} - static int tracing_open_pipe(struct inode *inode, struct file *filp) { struct trace_array *tr = inode->i_private; struct trace_iterator *iter; - int cpu; int ret; ret = tracing_check_open_get_tr(tr); @@ -6226,16 +6200,13 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) return ret; mutex_lock(&trace_types_lock); - cpu = tracing_get_cpu(inode); - ret = open_pipe_on_cpu(tr, cpu); - if (ret) - goto fail_pipe_on_cpu; /* create a buffer to store the information to pass to userspace */ iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { ret = -ENOMEM; - goto fail_alloc_iter; + __trace_array_put(tr); + goto out; } trace_seq_init(&iter->seq); @@ -6258,7 +6229,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) iter->tr = tr; iter->array_buffer = &tr->array_buffer; - iter->cpu_file = cpu; + iter->cpu_file = tracing_get_cpu(inode); mutex_init(&iter->mutex); filp->private_data = iter; @@ -6268,15 +6239,12 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) nonseekable_open(inode, filp); tr->trace_ref++; - +out: mutex_unlock(&trace_types_lock); return ret; fail: kfree(iter); -fail_alloc_iter: - close_pipe_on_cpu(tr, cpu); -fail_pipe_on_cpu: __trace_array_put(tr); mutex_unlock(&trace_types_lock); return ret; @@ -6293,7 +6261,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) if (iter->trace->pipe_close) iter->trace->pipe_close(iter); - close_pipe_on_cpu(tr, iter->cpu_file); + mutex_unlock(&trace_types_lock); free_cpumask_var(iter->started); @@ -8824,9 +8792,6 @@ static struct trace_array *trace_array_create(const char *name) if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL)) goto out_free_tr; - if (!alloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL)) - goto out_free_tr; - tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS; cpumask_copy(tr->tracing_cpumask, cpu_all_mask); @@ -8868,7 +8833,6 @@ static struct trace_array *trace_array_create(const char *name) out_free_tr: ftrace_free_ftrace_ops(tr); free_trace_buffers(tr); - free_cpumask_var(tr->pipe_cpumask); free_cpumask_var(tr->tracing_cpumask); kfree(tr->name); kfree(tr); @@ -8970,7 +8934,6 @@ static int __remove_instance(struct trace_array *tr) } kfree(tr->topts); - free_cpumask_var(tr->pipe_cpumask); free_cpumask_var(tr->tracing_cpumask); kfree(tr->name); kfree(tr); @@ -9705,14 +9668,12 @@ __init static int tracer_alloc_buffers(void) if (trace_create_savedcmd() < 0) goto out_free_temp_buffer; - if (!alloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL)) - goto out_free_savedcmd; - /* TODO: make the number of buffers hot pluggable with CPUS */ if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) { MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n"); - goto out_free_pipe_cpumask; + goto out_free_savedcmd; } + if (global_trace.buffer_disabled) tracing_off(); @@ -9763,8 +9724,6 @@ __init static int tracer_alloc_buffers(void) return 0; -out_free_pipe_cpumask: - free_cpumask_var(global_trace.pipe_cpumask); out_free_savedcmd: free_saved_cmdlines_buffer(savedcmd); out_free_temp_buffer: diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6b0c177012c2..e5b505b5b7d0 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -356,8 +356,6 @@ struct trace_array { struct list_head events; struct trace_event_file *trace_marker_file; cpumask_var_t tracing_cpumask; /* only trace on set CPUs */ - /* one per_cpu trace_pipe can be opened by only one user */ - cpumask_var_t pipe_cpumask; int ref; int trace_ref; #ifdef CONFIG_FUNCTION_TRACER