Hi! > From: Fedor Pchelkin <pchelkin@xxxxxxxxx> > > commit 902e02ea9385373ce4b142576eef41c642703955 upstream. > > Syzkaller reports the following problem: > > BUG: sleeping function called from invalid context at kernel/printk/printk.c:2347 > in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1105, name: syz-executor423 > 3 locks held by syz-executor423/1105: Does this happen in 5.10, too? printk locking changed significantly in recent years. > The problem happens in the following control flow: > > gsmld_write(...) > spin_lock_irqsave(&gsm->tx_lock, flags) // taken a spinlock on TX data > con_write(...) > do_con_write(...) > console_lock() > might_sleep() // -> bug > > As far as console_lock() might sleep it should not be called with > spinlock held. Ok. > The patch replaces tx_lock spinlock with mutex in order to avoid the > problem. Are you sure you can do that? Original code disabled interrupts, because parts of protected data were accessed from interrupt context, and you simply removed that protection. Best regards, Pavel -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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