@@ -336,7 +336,7 @@ static void blk_trace_cleanup(struct blk_trace *bt)
blk_unregister_tracepoints();
}
-int blk_trace_remove(struct request_queue *q)
+static int __blk_trace_remove(struct request_queue *q)
{
struct blk_trace *bt;
@@ -349,6 +349,17 @@ int blk_trace_remove(struct request_queue *q)
return 0;
}
+
+int blk_trace_remove(struct request_queue *q)
+{
+ int ret;
+
+ mutex_lock(&q->blk_trace_mutex);
+ ret = __blk_trace_remove(q);
+ mutex_unlock(&q->blk_trace_mutex);
+
+ return ret;
+}
EXPORT_SYMBOL_GPL(blk_trace_remove);
static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
@@ -550,9 +561,8 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
return ret;
}
-int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
- struct block_device *bdev,
- char __user *arg)
+static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+ struct block_device *bdev, char __user *arg)
{
struct blk_user_trace_setup buts;
int ret;
@@ -571,6 +581,19 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
}
return 0;
}
+
+int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+ struct block_device *bdev,
+ char __user *arg)
+{
+ int ret;
+
+ mutex_lock(&q->blk_trace_mutex);
+ ret = __blk_trace_setup(q, name, dev, bdev, arg);
+ mutex_unlock(&q->blk_trace_mutex);
+
+ return ret;
+}
EXPORT_SYMBOL_GPL(blk_trace_setup);
#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
@@ -607,7 +630,7 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
}
#endif
-int blk_trace_startstop(struct request_queue *q, int start)
+static int __blk_trace_startstop(struct request_queue *q, int start)
{
int ret;
struct blk_trace *bt = q->blk_trace;
@@ -646,6 +669,17 @@ int blk_trace_startstop(struct request_queue *q, int start)
return ret;
}
+
+int blk_trace_startstop(struct request_queue *q, int start)
+{
+ int ret;
+
+ mutex_lock(&q->blk_trace_mutex);
+ ret = __blk_trace_startstop(q, start);
+ mutex_unlock(&q->blk_trace_mutex);
+
+ return ret;
+}
EXPORT_SYMBOL_GPL(blk_trace_startstop);
/*
@@ -676,7 +710,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
switch (cmd) {
case BLKTRACESETUP:
bdevname(bdev, b);
- ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
+ ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
break;
#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
case BLKTRACESETUP32:
@@ -687,10 +721,10 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
case BLKTRACESTART:
start = 1;
case BLKTRACESTOP:
- ret = blk_trace_startstop(q, start);
+ ret = __blk_trace_startstop(q, start);
break;
case BLKTRACETEARDOWN:
- ret = blk_trace_remove(q);
+ ret = __blk_trace_remove(q);
break;
default:
ret = -ENOTTY;
@@ -708,10 +742,14 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
**/
void blk_trace_shutdown(struct request_queue *q)
{
+ mutex_lock(&q->blk_trace_mutex);
+
if (q->blk_trace) {
- blk_trace_startstop(q, 0);
- blk_trace_remove(q);
+ __blk_trace_startstop(q, 0);
+ __blk_trace_remove(q);
}
+
+ mutex_unlock(&q->blk_trace_mutex);
}
#ifdef CONFIG_BLK_CGROUP
sg.c calls into the blktrace functions without holding the proper queue mutex for doing setup, start/stop, or teardown. This can cause problems like the below: CPU: 0 PID: 2995 Comm: syzkaller857118 Not tainted 4.14.0-rc5-next-20171018+ #36 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 panic+0x1e4/0x41c kernel/panic.c:183 __warn+0x1c4/0x1e0 kernel/panic.c:546 report_bug+0x211/0x2d0 lib/bug.c:183 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:177 do_trap_no_signal arch/x86/kernel/traps.c:211 [inline] do_trap+0x260/0x390 arch/x86/kernel/traps.c:260 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:297 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:310 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905 RIP: 0010:tracepoint_add_func kernel/tracepoint.c:210 [inline] RIP: 0010:tracepoint_probe_register_prio+0x397/0x9a0 kernel/tracepoint.c:283 RSP: 0018:ffff8801d1d1f6c0 EFLAGS: 00010293 RAX: ffff8801d22e8540 RBX: 00000000ffffffef RCX: ffffffff81710f07 RDX: 0000000000000000 RSI: ffffffff85b679c0 RDI: ffff8801d5f19818 RBP: ffff8801d1d1f7c8 R08: ffffffff81710c10 R09: 0000000000000004 R10: ffff8801d1d1f6b0 R11: 0000000000000003 R12: ffffffff817597f0 R13: 0000000000000000 R14: 00000000ffffffff R15: ffff8801d1d1f7a0 tracepoint_probe_register+0x2a/0x40 kernel/tracepoint.c:304 register_trace_block_rq_insert include/trace/events/block.h:191 [inline] blk_register_tracepoints+0x1e/0x2f0 kernel/trace/blktrace.c:1043 do_blk_trace_setup+0xa10/0xcf0 kernel/trace/blktrace.c:542 blk_trace_setup+0xbd/0x180 kernel/trace/blktrace.c:564 sg_ioctl+0xc71/0x2d90 drivers/scsi/sg.c:1089 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x444339 RSP: 002b:00007ffe05bb5b18 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006d66c0 RCX: 0000000000444339 RDX: 000000002084cf90 RSI: 00000000c0481273 RDI: 0000000000000009 RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: ffffffffffffffff R13: 00000000c0481273 R14: 0000000000000000 R15: 0000000000000000 since we can now run these in parallel. Ensure that the exported helpers for doing this are grabbing the queue trace mutex. Reported-by: Steven Rostedt <rostedt@goodmis.org> Fixes: 6da127ad0918 ("blktrace: Add blktrace ioctls to SCSI generic devices") Signed-off-by: Jens Axboe <axboe@kernel.dk> ---