ACPI / EC: Fix race condition in ec_transaction_completed()
commit c0d653412f
upstream.
There is a race condition in ec_transaction_completed().
When ec_transaction_completed() is called in the GPE handler, it could
return true because of (ec->curr == NULL). Then the wake_up() invocation
could complete the next command unexpectedly since there is no lock between
the 2 invocations. With the previous cleanup, the IBF=0 waiter race need
not be handled any more. It's now safe to return a flag from
advance_condition() to indicate the requirement of wakeup, the flag is
returned from a locked context.
The ec_transaction_completed() is now only invoked by the ec_poll() where
the ec->curr is ensured to be different from NULL.
After cleaning up, the EVT_SCI=1 check should be moved out of the wakeup
condition so that an EVT_SCI raised with (ec->curr == NULL) can trigger a
QR_SC command.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=70891
Link: https://bugzilla.kernel.org/show_bug.cgi?id=63931
Link: https://bugzilla.kernel.org/show_bug.cgi?id=59911
Reported-and-tested-by: Gareth Williams <gareth@garethwilliams.me.uk>
Reported-and-tested-by: Hans de Goede <jwrdegoede@fedoraproject.org>
Reported-by: Barton Xu <tank.xuhan@gmail.com>
Tested-by: Steffen Weber <steffen.weber@gmail.com>
Tested-by: Arthur Chen <axchen@nvidia.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
3506335c49
commit
8d706077c2
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@ -158,16 +158,17 @@ static int ec_transaction_completed(struct acpi_ec *ec)
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unsigned long flags;
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int ret = 0;
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spin_lock_irqsave(&ec->lock, flags);
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if (!ec->curr || (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
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if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
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ret = 1;
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spin_unlock_irqrestore(&ec->lock, flags);
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return ret;
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}
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static void advance_transaction(struct acpi_ec *ec)
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static bool advance_transaction(struct acpi_ec *ec)
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{
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struct transaction *t;
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u8 status;
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bool wakeup = false;
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pr_debug("===== %s =====\n", in_interrupt() ? "IRQ" : "TASK");
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status = acpi_ec_read_status(ec);
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@ -183,21 +184,25 @@ static void advance_transaction(struct acpi_ec *ec)
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} else if (t->rlen > t->ri) {
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if ((status & ACPI_EC_FLAG_OBF) == 1) {
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t->rdata[t->ri++] = acpi_ec_read_data(ec);
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if (t->rlen == t->ri)
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if (t->rlen == t->ri) {
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t->flags |= ACPI_EC_COMMAND_COMPLETE;
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wakeup = true;
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}
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} else
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goto err;
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} else if (t->wlen == t->wi &&
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(status & ACPI_EC_FLAG_IBF) == 0)
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(status & ACPI_EC_FLAG_IBF) == 0) {
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t->flags |= ACPI_EC_COMMAND_COMPLETE;
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return;
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wakeup = true;
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}
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return wakeup;
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} else {
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if ((status & ACPI_EC_FLAG_IBF) == 0) {
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acpi_ec_write_cmd(ec, t->command);
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t->flags |= ACPI_EC_COMMAND_POLL;
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} else
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goto err;
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return;
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return wakeup;
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}
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err:
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/*
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@ -208,13 +213,14 @@ err:
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if (in_interrupt() && t)
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++t->irq_count;
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}
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return wakeup;
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}
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static void start_transaction(struct acpi_ec *ec)
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{
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ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
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ec->curr->flags = 0;
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advance_transaction(ec);
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(void)advance_transaction(ec);
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}
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static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data);
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@ -248,7 +254,7 @@ static int ec_poll(struct acpi_ec *ec)
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return 0;
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}
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spin_lock_irqsave(&ec->lock, flags);
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advance_transaction(ec);
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(void)advance_transaction(ec);
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spin_unlock_irqrestore(&ec->lock, flags);
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} while (time_before(jiffies, delay));
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pr_debug("controller reset, restart transaction\n");
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@ -627,12 +633,10 @@ static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
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struct acpi_ec *ec = data;
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spin_lock_irqsave(&ec->lock, flags);
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advance_transaction(ec);
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spin_unlock_irqrestore(&ec->lock, flags);
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if (ec_transaction_completed(ec)) {
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if (advance_transaction(ec))
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wake_up(&ec->wait);
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ec_check_sci(ec, acpi_ec_read_status(ec));
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}
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spin_unlock_irqrestore(&ec->lock, flags);
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ec_check_sci(ec, acpi_ec_read_status(ec));
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return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
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}
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