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power: supply: pf1550: Fix use-after-free in power_supply_changed()

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Using the `devm_` variant for requesting IRQ _before_ the `devm_`
variant for allocating/registering the `power_supply` handle, means that
the `power_supply` handle will be deallocated/unregistered _before_ the
interrupt handler (since `devm_` naturally deallocates in reverse
allocation order). This means that during removal, there is a race
condition where an interrupt can fire just _after_ the `power_supply`
handle has been freed, *but* just _before_ the corresponding
unregistration of the IRQ handler has run.

This will lead to the IRQ handler calling `power_supply_changed()` with
a freed `power_supply` handle. Which usually crashes the system or
otherwise silently corrupts the memory...

Note that there is a similar situation which can also happen during
`probe()`; the possibility of an interrupt firing _before_ registering
the `power_supply` handle. This would then lead to the nasty situation
of using the `power_supply` handle *uninitialized* in
`power_supply_changed()`.

Fix this racy use-after-free by making sure the IRQ is requested _after_
the registration of the `power_supply` handle.

Fixes: 4b6b6433a9 ("power: supply: pf1550: add battery charger support")
Signed-off-by: Waqar Hameed <waqar.hameed@axis.com>
Reviewed-by: Samuel Kayode <samkay014@gmail.com>
Link: https://patch.msgid.link/ae5a71b7e4dd2967d8fdcc531065cc71b17c86f5.1766268280.git.waqar.hameed@axis.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
This commit is contained in:
Waqar Hameed
2025-12-20 23:36:01 +01:00
committed by Sebastian Reichel
parent b2ce982e2e
commit 838767f507
1 changed files with 16 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
drivers/power/supply/pf1550-charger.c
View File

@@ -584,22 +584,6 @@ static int pf1550_charger_probe(struct platform_device *pdev)
return dev_err_probe(chg->dev, ret,
"failed to add battery sense work\n");
for (i = 0; i < PF1550_CHARGER_IRQ_NR; i++) {
irq = platform_get_irq(pdev, i);
if (irq < 0)
return irq;
chg->virqs[i] = irq;
ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
pf1550_charger_irq_handler,
IRQF_NO_SUSPEND,
"pf1550-charger", chg);
if (ret)
return dev_err_probe(&pdev->dev, ret,
"failed irq request\n");
}
psy_cfg.drv_data = chg;
chg->charger = devm_power_supply_register(&pdev->dev,
@@ -616,6 +600,22 @@ static int pf1550_charger_probe(struct platform_device *pdev)
return dev_err_probe(&pdev->dev, PTR_ERR(chg->battery),
"failed: power supply register\n");
for (i = 0; i < PF1550_CHARGER_IRQ_NR; i++) {
irq = platform_get_irq(pdev, i);
if (irq < 0)
return irq;
chg->virqs[i] = irq;
ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
pf1550_charger_irq_handler,
IRQF_NO_SUSPEND,
"pf1550-charger", chg);
if (ret)
return dev_err_probe(&pdev->dev, ret,
"failed irq request\n");
}
pf1550_dt_parse_dev_info(chg);
return pf1550_reg_init(chg);