From: Anton Volkov <avolkov@ispras.ru>
To: isdn@linux-pingi.de, davem@davemloft.net, calle@calle.de
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
ldv-project@linuxtesting.org,
Alexey Khoroshilov <khoroshilov@ispras.ru>
Subject: Possible race in c4.ko
Date: Tue, 15 Aug 2017 16:22:16 +0300 [thread overview]
Message-ID: <b839c418-9c1d-aba7-4d00-e9c7786870bf@ispras.ru> (raw)
Hello.
While searching for races in the Linux kernel I've come across
"drivers/isdn/hardware/avm/c4.ko" module. Here is a question that I came
up with while analyzing results. Lines are given using the info from
Linux v4.12.
Consider the following case:
Thread 1: Thread 2:
c4_probe
->c4_add_card
request_irq()
c4_interrupt
->c4_handle_interrupt
->c4_handle_rx
card->cardnr = ... cidx = f(card->cardnr)
(c4.c: line 1227) (c4.c: line 526)
if (cidx >= card->nlogcontr) cidx = 0;
ctrl = &card->ctrlinfo[cidx].capi_ctrl
card->cardnr is 0 until it is initialized in c4_add_card(). If at the
moment of read access in c4_handle_rx() it is still 0, cidx may then be
assigned an undesirable value and wrong controller may handle messages.
Is this case feasible from your point of view?
Thank you for your time.
-- Anton Volkov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
e-mail: avolkov@ispras.ru
next reply other threads:[~2017-08-15 13:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-15 13:22 Anton Volkov [this message]
2017-08-16 4:55 ` Possible race in c4.ko Carsten Paeth
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