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author | Ingo Molnar <mingo@elte.hu> | 2008-11-19 10:00:15 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-11-19 10:00:15 +0100 |
commit | 86fa2f60674540df0b34f5c547ed0c1cf3a8f212 (patch) | |
tree | a367d69ad41f46362dfdb8eaf19ec8a6f8a8c812 /kernel/trace | |
parent | a22506347d038a66506c6f57e9b97104128e280d (diff) | |
download | kernel_samsung_smdk4412-86fa2f60674540df0b34f5c547ed0c1cf3a8f212.zip kernel_samsung_smdk4412-86fa2f60674540df0b34f5c547ed0c1cf3a8f212.tar.gz kernel_samsung_smdk4412-86fa2f60674540df0b34f5c547ed0c1cf3a8f212.tar.bz2 |
ftrace: fix selftest locking
Impact: fix self-test boot crash
Self-test failure forgot to re-lock the BKL - crashing the next
initcall:
Testing tracer irqsoff: .. no entries found ..FAILED!
initcall init_irqsoff_tracer+0x0/0x11 returned 0 after 3906 usecs
calling init_mmio_trace+0x0/0xf @ 1
------------[ cut here ]------------
Kernel BUG at c0c0a915 [verbose debug info unavailable]
invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
last sysfs file:
Pid: 1, comm: swapper Not tainted (2.6.28-rc5-tip #53704)
EIP: 0060:[<c0c0a915>] EFLAGS: 00010286 CPU: 1
EIP is at unlock_kernel+0x10/0x2b
EAX: ffffffff EBX: 00000000 ECX: 00000000 EDX: f7030000
ESI: c12da19c EDI: 00000000 EBP: f7039f54 ESP: f7039f54
DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process swapper (pid: 1, ti=f7038000 task=f7030000 task.ti=f7038000)
Stack:
f7039f6c c0164d30 c013fed8 a7d8d7b4 00000000 00000000 f7039f74 c12fb78a
f7039fd0 c0101132 c12fb77d 00000000 6f727200 6f632072 2d206564 c1002031
0000000f f7039fa2 f7039fb0 3531b171 00000000 00000000 0000002f c12ca480
Call Trace:
[<c0164d30>] ? register_tracer+0x66/0x13f
[<c013fed8>] ? ktime_get+0x19/0x1b
[<c12fb78a>] ? init_mmio_trace+0xd/0xf
[<c0101132>] ? do_one_initcall+0x4a/0x111
[<c12fb77d>] ? init_mmio_trace+0x0/0xf
[<c015c7e6>] ? init_irq_proc+0x46/0x59
[<c12e851d>] ? kernel_init+0x104/0x152
[<c12e8419>] ? kernel_init+0x0/0x152
[<c01038b7>] ? kernel_thread_helper+0x7/0x10
Code: 58 14 43 75 0a b8 00 9b 2d c1 e8 51 43 7a ff 64 a1 00 a0 37 c1 89 58 14 5b 5d c3 55 64 8b 15 00 a0 37 c1 83 7a 14 00 89 e5 79 04 <0f> 0b eb fe 8b 42 14 48 85 c0 89 42 14 79 0a b8 00 9b 2d c1 e8
EIP: [<c0c0a915>] unlock_kernel+0x10/0x2b SS:ESP 0068:f7039f54
---[ end trace a7919e7f17c0a725 ]---
Kernel panic - not syncing: Attempted to kill init!
So clean up the flow a bit.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace')
-rw-r--r-- | kernel/trace/trace.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1689212..24b6238 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -520,7 +520,15 @@ int register_tracer(struct tracer *type) return -1; } + /* + * When this gets called we hold the BKL which means that + * preemption is disabled. Various trace selftests however + * need to disable and enable preemption for successful tests. + * So we drop the BKL here and grab it after the tests again. + */ + unlock_kernel(); mutex_lock(&trace_types_lock); + for (t = trace_types; t; t = t->next) { if (strcmp(type->name, t->name) == 0) { /* already found */ @@ -532,13 +540,6 @@ int register_tracer(struct tracer *type) } #ifdef CONFIG_FTRACE_STARTUP_TEST - /* - * When this gets called we hold the BKL which means that preemption - * is disabled. Various trace selftests however need to disable - * and enable preemption for successful tests. So we drop the BKL here - * and grab it after the tests again. - */ - unlock_kernel(); if (type->selftest) { struct tracer *saved_tracer = current_trace; struct trace_array *tr = &global_trace; @@ -550,9 +551,9 @@ int register_tracer(struct tracer *type) * internal tracing to verify that everything is in order. * If we fail, we do not register this tracer. */ - for_each_tracing_cpu(i) { + for_each_tracing_cpu(i) tracing_reset(tr, i); - } + current_trace = type; /* the test is responsible for initializing and enabling */ pr_info("Testing tracer %s: ", type->name); @@ -564,12 +565,11 @@ int register_tracer(struct tracer *type) goto out; } /* Only reset on passing, to avoid touching corrupted buffers */ - for_each_tracing_cpu(i) { + for_each_tracing_cpu(i) tracing_reset(tr, i); - } + printk(KERN_CONT "PASSED\n"); } - lock_kernel(); #endif type->next = trace_types; @@ -580,6 +580,7 @@ int register_tracer(struct tracer *type) out: mutex_unlock(&trace_types_lock); + lock_kernel(); return ret; } |