Hi, I got this today when boot gta04 machine (dts is mostly same as for beagle-xm) on today's linux-next (with 3.11-rc4 it's not happening):
[ 4.404602] ====================================================== [ 4.411102] [ INFO: possible circular locking dependency detected ] [ 4.417694] 3.11.0-rc4-next-20130807-dirty #2 Not tainted [ 4.423339] ------------------------------------------------------- [ 4.429931] getty/767 is trying to acquire lock: [ 4.434783] (&tty->termios_rwsem){++++..}, at: [<c0308f24>] n_tty_read+0x3ec/0x958 [ 4.442871] [ 4.442871] but task is already holding lock: [ 4.449005] (&ldata->atomic_read_lock){+.+...}, at: [<c0309100>] n_tty_read+0x5c8/0x958 [ 4.457519] [ 4.457519] which lock already depends on the new lock. [ 4.457519] [ 4.466094] [ 4.466094] the existing dependency chain (in reverse order) is: [ 4.473968] -> #1 (&ldata->atomic_read_lock){+.+...}: [ 4.479461] [<c0099800>] lock_acquire+0xa0/0xfc [ 4.484893] [<c0508a34>] mutex_lock_interruptible_nested+0x4c/0x420 [ 4.492126] [<c0309100>] n_tty_read+0x5c8/0x958 [ 4.497528] [<c030367c>] tty_read+0x78/0xc8 [ 4.502563] [<c0112ba8>] vfs_read+0x98/0x140 [ 4.507690] [<c01132a0>] SyS_read+0x3c/0x78 [ 4.512725] [<c0013b00>] ret_fast_syscall+0x0/0x48 [ 4.518432] -> #0 (&tty->termios_rwsem){++++..}: [ 4.523468] [<c0098e50>] __lock_acquire+0x195c/0x1b08 [ 4.529418] [<c0099800>] lock_acquire+0xa0/0xfc [ 4.534820] [<c050a178>] down_read+0x30/0x40 [ 4.539947] [<c0308f24>] n_tty_read+0x3ec/0x958 [ 4.545349] [<c030367c>] tty_read+0x78/0xc8 [ 4.550384] [<c0112ba8>] vfs_read+0x98/0x140 [ 4.555511] [<c01132a0>] SyS_read+0x3c/0x78 [ 4.560546] [<c0013b00>] ret_fast_syscall+0x0/0x48 [ 4.566253] [ 4.566253] other info that might help us debug this: [ 4.566253] [ 4.574645] Possible unsafe locking scenario: [ 4.574645] [ 4.580871] CPU0 CPU1 [ 4.585601] ---- ---- [ 4.590362] lock(&ldata->atomic_read_lock); [ 4.594940] lock(&tty->termios_rwsem); [ 4.601715] lock(&ldata->atomic_read_lock); [ 4.608947] lock(&tty->termios_rwsem); [ 4.613067] [ 4.613067] *** DEADLOCK *** [ 4.613067] [ 4.619293] 2 locks held by getty/767: [ 4.623229] #0: (&tty->ldisc_sem){.+.+.+}, at: [<c030ac84>] tty_ldisc_ref_wait+0x14/0x3c [ 4.631958] #1: (&ldata->atomic_read_lock){+.+...}, at: [<c0309100>] n_tty_read+0x5c8/0x958 [ 4.640930] [ 4.640930] stack backtrace: [ 4.645507] CPU: 0 PID: 767 Comm: getty Not tainted 3.11.0-rc4-next-20130807-dirty #2 [ 4.653778] [<c001b8a4>] (unwind_backtrace+0x0/0xec) from [<c0017af8>] (show_stack+0x10/0x14) [ 4.662719] [<c0017af8>] (show_stack+0x10/0x14) from [<c0506c88>] (dump_stack+0x7c/0x94) [ 4.671234] [<c0506c88>] (dump_stack+0x7c/0x94) from [<c0504abc>] (print_circular_bug+0x27c/0x2d0) [ 4.680633] [<c0504abc>] (print_circular_bug+0x27c/0x2d0) from [<c0098e50>] (__lock_acquire+0x195c/0x1b08) [ 4.690795] [<c0098e50>] (__lock_acquire+0x195c/0x1b08) from [<c0099800>] (lock_acquire+0xa0/0xfc) [ 4.700195] [<c0099800>] (lock_acquire+0xa0/0xfc) from [<c050a178>] (down_read+0x30/0x40) [ 4.708801] [<c050a178>] (down_read+0x30/0x40) from [<c0308f24>] (n_tty_read+0x3ec/0x958) [ 4.717407] [<c0308f24>] (n_tty_read+0x3ec/0x958) from [<c030367c>] (tty_read+0x78/0xc8) [ 4.725891] [<c030367c>] (tty_read+0x78/0xc8) from [<c0112ba8>] (vfs_read+0x98/0x140) [ 4.734130] [<c0112ba8>] (vfs_read+0x98/0x140) from [<c01132a0>] (SyS_read+0x3c/0x78) [ 4.742370] [<c01132a0>] (SyS_read+0x3c/0x78) from [<c0013b00>] (ret_fast_syscall+0x0/0x48) marek -- as simple and primitive as possible ------------------------------------------------- Marek Belisko - OPEN-NANDRA Freelance Developer Ruska Nova Ves 219 | Presov, 08005 Slovak Republic Tel: +421 915 052 184 skype: marekwhite twitter: #opennandra web: http://open-nandra.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/