Package: src:linux
Version: 3.9.6-1
Severity: normal
Tags: upstream
I have compiled kernel with lockdep support from linux-source-3.9 package;
config was taken from 3.9-1-amd64 + some debug options on (including
lockdep). I get following messages:
[ 600.453133] ==
[ 600.453133] [ INFO: possible circular locking dependency detected ]
[ 600.453134] 3.9.6-1-debug-amd64 #1 Tainted: GW O
[ 600.453135] ---
[ 600.453135] kworker/0:0/4 is trying to acquire lock:
[ 600.453140] (fb_info-lock){+.+.+.}, at: [81242e88]
lock_fb_info+0x18/0x37
[ 600.453141]
[ 600.453141] but task is already holding lock:
[ 600.453144] (console_lock){+.+.+.}, at: [812ae160]
console_callback+0xa/0xf3
[ 600.453144]
[ 600.453144] which lock already depends on the new lock.
[ 600.453144]
[ 600.453144]
[ 600.453144] the existing dependency chain (in reverse order) is:
[ 600.453145]
[ 600.453145] - #1 (console_lock){+.+.+.}:
[ 600.453148][81092274] lock_acquire+0x10a/0x15f
[ 600.453150][81044551] console_lock+0x69/0x6b
[ 600.453151][81243c57] register_framebuffer+0x201/0x278
[ 600.453153][81af4aea] efifb_probe+0x408/0x48f
[ 600.453156][812cd81c] platform_drv_probe+0x34/0x5e
[ 600.453157][812cc00d] driver_probe_device+0x98/0x1b1
[ 600.453159][812cc174] __driver_attach+0x4e/0x6f
[ 600.453160][812ca7bf] bus_for_each_dev+0x57/0x8a
[ 600.453161][812cbb2c] driver_attach+0x19/0x1b
[ 600.453162][812cb7d0] bus_add_driver+0xde/0x201
[ 600.453164][812cc6db] driver_register+0x8c/0x110
[ 600.453165][812cd2b1] platform_driver_register+0x41/0x43
[ 600.453167][812cd2cb] platform_driver_probe+0x18/0x8a
[ 600.453168][81af46c3] efifb_init+0x276/0x295
[ 600.453170][810020b4] do_one_initcall+0x7a/0x136
[ 600.453172][81ac7ecf] kernel_init_freeable+0x13f/0x1cc
[ 600.453174][813de02a] kernel_init+0x9/0xd6
[ 600.453177][814005bc] ret_from_fork+0x7c/0xb0
[ 600.453178]
[ 600.453178] - #0 (fb_info-lock){+.+.+.}:
[ 600.453179][81091a17] __lock_acquire+0xa64/0xdc0
[ 600.453180][81092274] lock_acquire+0x10a/0x15f
[ 600.453182][813f81b7] __mutex_lock_common+0x5d/0x371
[ 600.453183][813f85c6] mutex_lock_nested+0x3b/0x40
[ 600.453184][81242e88] lock_fb_info+0x18/0x37
[ 600.453185][8124cab2] fbcon_blank+0x168/0x1ee
[ 600.453187][812abc46] do_blank_screen+0x13e/0x1d8
[ 600.453188][812ae220] console_callback+0xca/0xf3
[ 600.453190][8105d4b3] process_one_work+0x249/0x416
[ 600.453191][8105dea6] worker_thread+0x121/0x1ce
[ 600.453193][81065b2d] kthread+0xac/0xb4
[ 600.453194][814005bc] ret_from_fork+0x7c/0xb0
[ 600.453194]
[ 600.453194] other info that might help us debug this:
[ 600.453194]
[ 600.453195] Possible unsafe locking scenario:
[ 600.453195]
[ 600.453195]CPU0CPU1
[ 600.453195]
[ 600.453196] lock(console_lock);
[ 600.453197]lock(fb_info-lock);
[ 600.453197]lock(console_lock);
[ 600.453198] lock(fb_info-lock);
[ 600.453198]
[ 600.453198] *** DEADLOCK ***
[ 600.453198]
[ 600.453199] 3 locks held by kworker/0:0/4:
[ 600.453201] #0: (events){.+.+.+}, at: [8105d3e9]
process_one_work+0x17f/0x416
[ 600.453203] #1: (console_work){+.+...}, at: [8105d3e9]
process_one_work+0x17f/0x416
[ 600.453205] #2: (console_lock){+.+.+.}, at: [812ae160]
console_callback+0xa/0xf3
[ 600.453205]
[ 600.453205] stack backtrace:
[ 600.453206] Pid: 4, comm: kworker/0:0 Tainted: GW O
3.9.6-1-debug-amd64 #1
[ 600.453206] Call Trace:
[ 600.453209] [813f39d3] print_circular_bug+0x1f6/0x204
[ 600.453211] [81091a17] __lock_acquire+0xa64/0xdc0
[ 600.453212] [81092274] lock_acquire+0x10a/0x15f
[ 600.453213] [81242e88] ? lock_fb_info+0x18/0x37
[ 600.453214] [813f81b7] __mutex_lock_common+0x5d/0x371
[ 600.453216] [81242e88] ? lock_fb_info+0x18/0x37
[ 600.453217] [81242e88] ? lock_fb_info+0x18/0x37
[ 600.453218] [8108f45d] ? lock_is_held+0x4e/0x5f
[ 600.453219] [813f85c6] mutex_lock_nested+0x3b/0x40
[ 600.453220] [81242e88] lock_fb_info+0x18/0x37
[ 600.453221] [8124cab2] fbcon_blank+0x168/0x1ee
[ 600.453223] [810926d2] ? trace_hardirqs_on_caller+0x117/0x173
[ 600.453224] [813fa6a5] ? _raw_spin_unlock_irqrestore+0x48/0x5c
[
