firewire: core: fix race condition in split transaction handling

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For a split transaction, either fw_core_handle_response() or
split_transaction_timeout_callback() may manipulate the same transaction
entry in the pending transaction list. The return value of timer_delete()
is used to determine which function handles the entry. If the transaction
is a split transaction and timer_delete() returns zero, the timeout
callback may already be running. In this case, the response handler must
leave the entry in the list for the timeout callback to remove.

A previous code refactoring broke this behavior, introducing a race
condition in which both functions could process the same transaction.
This could lead to a use-after-free on the transaction initiator side.

Fix the regression by ensuring that the response handler does not process
the transaction when timer_delete() returns zero. The timeout callback is
responsible for removing the entry from the pending transaction list.

Fixes: fa2dc27100 ("firewire: core: code refactoring to find and pop transaction entry")
Link: https://lore.kernel.org/r/20261018025504.290598-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

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Takashi Sakamoto 2026-10-18 11:55:04 +09:00

parent 24a19b953e

commit 7f9f2d6abc

1 changed files with 6 additions and 2 deletions

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drivers/firewire/core-transaction.c

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