| From ef99b88b16bee753fa51207abdc58ae660453ec6 Mon Sep 17 00:00:00 2001 |
| From: Rabin Vincent <rabin@rab.in> |
| Date: Mon, 13 Apr 2015 22:30:12 +0200 |
| Subject: tracing: Handle ftrace_dump() atomic context in graph_trace_open() |
| |
| From: Rabin Vincent <rabin@rab.in> |
| |
| commit ef99b88b16bee753fa51207abdc58ae660453ec6 upstream. |
| |
| graph_trace_open() can be called in atomic context from ftrace_dump(). |
| Use GFP_ATOMIC for the memory allocations when that's the case, in order |
| to avoid the following splat. |
| |
| BUG: sleeping function called from invalid context at mm/slab.c:2849 |
| in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/0 |
| Backtrace: |
| .. |
| [<8004dc94>] (__might_sleep) from [<801371f4>] (kmem_cache_alloc_trace+0x160/0x238) |
| r7:87800040 r6:000080d0 r5:810d16e8 r4:000080d0 |
| [<80137094>] (kmem_cache_alloc_trace) from [<800cbd60>] (graph_trace_open+0x30/0xd0) |
| r10:00000100 r9:809171a8 r8:00008e28 r7:810d16f0 r6:00000001 r5:810d16e8 |
| r4:810d16f0 |
| [<800cbd30>] (graph_trace_open) from [<800c79c4>] (trace_init_global_iter+0x50/0x9c) |
| r8:00008e28 r7:808c853c r6:00000001 r5:810d16e8 r4:810d16f0 r3:800cbd30 |
| [<800c7974>] (trace_init_global_iter) from [<800c7aa0>] (ftrace_dump+0x90/0x2ec) |
| r4:810d2580 r3:00000000 |
| [<800c7a10>] (ftrace_dump) from [<80414b2c>] (sysrq_ftrace_dump+0x1c/0x20) |
| r10:00000100 r9:809171a8 r8:808f6e7c r7:00000001 r6:00000007 r5:0000007a |
| r4:808d5394 |
| [<80414b10>] (sysrq_ftrace_dump) from [<800169b8>] (return_to_handler+0x0/0x18) |
| [<80415498>] (__handle_sysrq) from [<800169b8>] (return_to_handler+0x0/0x18) |
| r8:808c8100 r7:808c8444 r6:00000101 r5:00000010 r4:84eb3210 |
| [<80415668>] (handle_sysrq) from [<800169b8>] (return_to_handler+0x0/0x18) |
| [<8042a760>] (pl011_int) from [<800169b8>] (return_to_handler+0x0/0x18) |
| r10:809171bc r9:809171a8 r8:00000001 r7:00000026 r6:808c6000 r5:84f01e60 |
| r4:8454fe00 |
| [<8007782c>] (handle_irq_event_percpu) from [<80077b44>] (handle_irq_event+0x4c/0x6c) |
| r10:808c7ef0 r9:87283e00 r8:00000001 r7:00000000 r6:8454fe00 r5:84f01e60 |
| r4:84f01e00 |
| [<80077af8>] (handle_irq_event) from [<8007aa28>] (handle_fasteoi_irq+0xf0/0x1ac) |
| r6:808f52a4 r5:84f01e60 r4:84f01e00 r3:00000000 |
| [<8007a938>] (handle_fasteoi_irq) from [<80076dc0>] (generic_handle_irq+0x3c/0x4c) |
| r6:00000026 r5:00000000 r4:00000026 r3:8007a938 |
| [<80076d84>] (generic_handle_irq) from [<80077128>] (__handle_domain_irq+0x8c/0xfc) |
| r4:808c1e38 r3:0000002e |
| [<8007709c>] (__handle_domain_irq) from [<800087b8>] (gic_handle_irq+0x34/0x6c) |
| r10:80917748 r9:00000001 r8:88802100 r7:808c7ef0 r6:808c8fb0 r5:00000015 |
| r4:8880210c r3:808c7ef0 |
| [<80008784>] (gic_handle_irq) from [<80014044>] (__irq_svc+0x44/0x7c) |
| |
| Link: http://lkml.kernel.org/r/1428953721-31349-1-git-send-email-rabin@rab.in |
| Link: http://lkml.kernel.org/r/1428957012-2319-1-git-send-email-rabin@rab.in |
| |
| Signed-off-by: Rabin Vincent <rabin@rab.in> |
| Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/trace/trace_functions_graph.c | 8 ++++++-- |
| 1 file changed, 6 insertions(+), 2 deletions(-) |
| |
| --- a/kernel/trace/trace_functions_graph.c |
| +++ b/kernel/trace/trace_functions_graph.c |
| @@ -1309,15 +1309,19 @@ void graph_trace_open(struct trace_itera |
| { |
| /* pid and depth on the last trace processed */ |
| struct fgraph_data *data; |
| + gfp_t gfpflags; |
| int cpu; |
| |
| iter->private = NULL; |
| |
| - data = kzalloc(sizeof(*data), GFP_KERNEL); |
| + /* We can be called in atomic context via ftrace_dump() */ |
| + gfpflags = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL; |
| + |
| + data = kzalloc(sizeof(*data), gfpflags); |
| if (!data) |
| goto out_err; |
| |
| - data->cpu_data = alloc_percpu(struct fgraph_cpu_data); |
| + data->cpu_data = alloc_percpu_gfp(struct fgraph_cpu_data, gfpflags); |
| if (!data->cpu_data) |
| goto out_err_free; |
| |