Hi RAGHU, Thank you for the patch! Perhaps something to improve:
url: https://github.com/0day-ci/linux/commits/RAGHU-Halharvi/genirq-Dereference-desc-after-null-pointer-check/20180717-150842 smatch warnings: kernel/irq/manage.c:1571 __free_irq() error: uninitialized symbol 'irq'. # https://github.com/0day-ci/linux/commit/3ebb02d34bcb1c8111a79856326bca85fb3321eb git remote add linux-review https://github.com/0day-ci/linux git remote update linux-review git checkout 3ebb02d34bcb1c8111a79856326bca85fb3321eb vim +/irq +1571 kernel/irq/manage.c d3c60047 Thomas Gleixner 2008-10-16 1560 cbf94f06 Magnus Damm 2009-03-12 1561 /* cbf94f06 Magnus Damm 2009-03-12 1562 * Internal function to unregister an irqaction - used to free cbf94f06 Magnus Damm 2009-03-12 1563 * regular and special interrupts that are part of the architecture. ^1da177e Linus Torvalds 2005-04-16 1564 */ 83ac4ca9 Uwe Kleine König 2018-03-19 1565 static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id) ^1da177e Linus Torvalds 2005-04-16 1566 { 3ebb02d3 RAGHU Halharvi 2018-07-17 1567 unsigned int irq; f17c7545 Ingo Molnar 2009-02-17 1568 struct irqaction *action, **action_ptr; ^1da177e Linus Torvalds 2005-04-16 1569 unsigned long flags; ^1da177e Linus Torvalds 2005-04-16 1570 ae88a23b Ingo Molnar 2009-02-15 @1571 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq); ^^^ Not initialized. 7d94f7ca Yinghai Lu 2008-08-19 1572 7d94f7ca Yinghai Lu 2008-08-19 1573 if (!desc) f21cfb25 Magnus Damm 2009-03-12 1574 return NULL; ^1da177e Linus Torvalds 2005-04-16 1575 3ebb02d3 RAGHU Halharvi 2018-07-17 1576 irq = desc->irq_data.irq; 9114014c Thomas Gleixner 2017-06-29 1577 mutex_lock(&desc->request_mutex); abc7e40c Thomas Gleixner 2015-12-13 1578 chip_bus_lock(desc); 239007b8 Thomas Gleixner 2009-11-17 1579 raw_spin_lock_irqsave(&desc->lock, flags); ae88a23b Ingo Molnar 2009-02-15 1580 ae88a23b Ingo Molnar 2009-02-15 1581 /* ae88a23b Ingo Molnar 2009-02-15 1582 * There can be multiple actions per IRQ descriptor, find the right ae88a23b Ingo Molnar 2009-02-15 1583 * one based on the dev_id: ae88a23b Ingo Molnar 2009-02-15 1584 */ f17c7545 Ingo Molnar 2009-02-17 1585 action_ptr = &desc->action; ^1da177e Linus Torvalds 2005-04-16 1586 for (;;) { f17c7545 Ingo Molnar 2009-02-17 1587 action = *action_ptr; ^1da177e Linus Torvalds 2005-04-16 1588 ae88a23b Ingo Molnar 2009-02-15 1589 if (!action) { ae88a23b Ingo Molnar 2009-02-15 1590 WARN(1, "Trying to free already-free IRQ %d\n", irq); 239007b8 Thomas Gleixner 2009-11-17 1591 raw_spin_unlock_irqrestore(&desc->lock, flags); abc7e40c Thomas Gleixner 2015-12-13 1592 chip_bus_sync_unlock(desc); 19d39a38 Thomas Gleixner 2017-07-11 1593 mutex_unlock(&desc->request_mutex); f21cfb25 Magnus Damm 2009-03-12 1594 return NULL; ae88a23b Ingo Molnar 2009-02-15 1595 } ^1da177e Linus Torvalds 2005-04-16 1596 8316e381 Ingo Molnar 2009-02-17 1597 if (action->dev_id == dev_id) ae88a23b Ingo Molnar 2009-02-15 1598 break; f17c7545 Ingo Molnar 2009-02-17 1599 action_ptr = &action->next; ae88a23b Ingo Molnar 2009-02-15 1600 } ^1da177e Linus Torvalds 2005-04-16 1601 ae88a23b Ingo Molnar 2009-02-15 1602 /* Found it - now remove it from the list of entries: */ f17c7545 Ingo Molnar 2009-02-17 1603 *action_ptr = action->next; dbce706e Paolo 'Blaisorblade' Giarrusso 2005-06-21 1604 cab303be Thomas Gleixner 2014-08-28 1605 irq_pm_remove_action(desc, action); cab303be Thomas Gleixner 2014-08-28 1606 ae88a23b Ingo Molnar 2009-02-15 1607 /* If this was the last handler, shut down the IRQ line: */ c1bacbae Thomas Gleixner 2014-03-08 1608 if (!desc->action) { e9849777 Thomas Gleixner 2015-10-09 1609 irq_settings_clr_disable_unlazy(desc); 46999238 Thomas Gleixner 2011-02-02 1610 irq_shutdown(desc); c1bacbae Thomas Gleixner 2014-03-08 1611 } 3aa551c9 Thomas Gleixner 2009-03-23 1612 :::::: The code at line 1571 was first introduced by commit :::::: ae88a23b32fa7e0dc9fa7ce735966e68eb41b0bc irq: refactor and clean up the free_irq() code flow :::::: TO: Ingo Molnar <[email protected]> :::::: CC: Ingo Molnar <[email protected]> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
