/* * kdb helper for dumping the ftrace buffer * * Copyright (C) 2010 Jason Wessel * * ftrace_dump_buf based on ftrace_dump: * Copyright (C) 2007-2008 Steven Rostedt * Copyright (C) 2008 Ingo Molnar * */ #include #include #include #include #include "trace.h" #include "trace_output.h" static void ftrace_dump_buf(int skip_lines, long cpu_file) { /* use static because iter can be a bit big for the stack */ static struct trace_iterator iter; static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS]; struct trace_array *tr; unsigned int old_userobj; int cnt = 0, cpu; trace_init_global_iter(&iter); iter.buffer_iter = buffer_iter; tr = iter.tr; for_each_tracing_cpu(cpu) { atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled); } old_userobj = tr->trace_flags; /* don't look at user memory in panic mode */ tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ; kdb_printf("Dumping ftrace buffer:\n"); /* reset all but tr, trace, and overruns */ memset(&iter.seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); iter.iter_flags |= TRACE_FILE_LAT_FMT; iter.pos = -1; if (cpu_file == RING_BUFFER_ALL_CPUS) { for_each_tracing_cpu(cpu) { iter.buffer_iter[cpu] = ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu); ring_buffer_read_start(iter.buffer_iter[cpu]); tracing_iter_reset(&iter, cpu); } } else { iter.cpu_file = cpu_file; iter.buffer_iter[cpu_file] = ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu_file); ring_buffer_read_start(iter.buffer_iter[cpu_file]); tracing_iter_reset(&iter, cpu_file); } while (trace_find_next_entry_inc(&iter)) { if (!cnt) kdb_printf("---------------------------------\n"); cnt++; if (!skip_lines) { print_trace_line(&iter); trace_printk_seq(&iter.seq); } else { skip_lines--; } if (KDB_FLAG(CMD_INTERRUPT)) goto out; } if (!cnt) kdb_printf(" (ftrace buffer empty)\n"); else kdb_printf("---------------------------------\n"); out: tr->trace_flags = old_userobj; for_each_tracing_cpu(cpu) { atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled); } for_each_tracing_cpu(cpu) { if (iter.buffer_iter[cpu]) { ring_buffer_read_finish(iter.buffer_iter[cpu]); iter.buffer_iter[cpu] = NULL; } } } /* * kdb_ftdump - Dump the ftrace log buffer */ static int kdb_ftdump(int argc, const char **argv) { int skip_lines = 0; long cpu_file; char *cp; if (argc > 2) return KDB_ARGCOUNT; if (argc) { skip_lines = simple_strtol(argv[1], &cp, 0); if (*cp) skip_lines = 0; } if (argc == 2) { cpu_file = simple_strtol(argv[2], &cp, 0); if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 || !cpu_online(cpu_file)) return KDB_BADINT; } else { cpu_file = RING_BUFFER_ALL_CPUS; } kdb_trap_printk++; ftrace_dump_buf(skip_lines, cpu_file); kdb_trap_printk--; return 0; } static __init int kdb_ftrace_register(void) { kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]", "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE); return 0; } late_initcall(kdb_ftrace_register); b268eef542c5414e54bf1a'>dt-bindings/mfd
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authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /include/dt-bindings/mfd
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'include/dt-bindings/mfd')