From: Wolfram Sang <wsa@kernel.org>
To: Dhananjay Phadke <dphadke@linux.microsoft.com>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
Ray Jui <rjui@broadcom.com>,
Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>,
bcm-kernel-feedback-list@broadcom.com
Subject: Re: [PATCH v3] i2c: iproc: fix race between client unreg and isr
Date: Wed, 12 Aug 2020 22:06:59 +0200 [thread overview]
Message-ID: <20200812200659.GA2324@kunai> (raw)
In-Reply-To: <1597106560-79693-1-git-send-email-dphadke@linux.microsoft.com>
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On Mon, Aug 10, 2020 at 05:42:40PM -0700, Dhananjay Phadke wrote:
> When i2c client unregisters, synchronize irq before setting
> iproc_i2c->slave to NULL.
>
> (1) disable_irq()
> (2) Mask event enable bits in control reg
> (3) Erase slave address (avoid further writes to rx fifo)
> (4) Flush tx and rx FIFOs
> (5) Clear pending event (interrupt) bits in status reg
> (6) enable_irq()
> (7) Set client pointer to NULL
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000318
>
> [ 371.020421] pc : bcm_iproc_i2c_isr+0x530/0x11f0
> [ 371.025098] lr : __handle_irq_event_percpu+0x6c/0x170
> [ 371.030309] sp : ffff800010003e40
> [ 371.033727] x29: ffff800010003e40 x28: 0000000000000060
> [ 371.039206] x27: ffff800010ca9de0 x26: ffff800010f895df
> [ 371.044686] x25: ffff800010f18888 x24: ffff0008f7ff3600
> [ 371.050165] x23: 0000000000000003 x22: 0000000001600000
> [ 371.055645] x21: ffff800010f18888 x20: 0000000001600000
> [ 371.061124] x19: ffff0008f726f080 x18: 0000000000000000
> [ 371.066603] x17: 0000000000000000 x16: 0000000000000000
> [ 371.072082] x15: 0000000000000000 x14: 0000000000000000
> [ 371.077561] x13: 0000000000000000 x12: 0000000000000001
> [ 371.083040] x11: 0000000000000000 x10: 0000000000000040
> [ 371.088519] x9 : ffff800010f317c8 x8 : ffff800010f317c0
> [ 371.093999] x7 : ffff0008f805b3b0 x6 : 0000000000000000
> [ 371.099478] x5 : ffff0008f7ff36a4 x4 : ffff8008ee43d000
> [ 371.104957] x3 : 0000000000000000 x2 : ffff8000107d64c0
> [ 371.110436] x1 : 00000000c00000af x0 : 0000000000000000
>
> [ 371.115916] Call trace:
> [ 371.118439] bcm_iproc_i2c_isr+0x530/0x11f0
> [ 371.122754] __handle_irq_event_percpu+0x6c/0x170
> [ 371.127606] handle_irq_event_percpu+0x34/0x88
> [ 371.132189] handle_irq_event+0x40/0x120
> [ 371.136234] handle_fasteoi_irq+0xcc/0x1a0
> [ 371.140459] generic_handle_irq+0x24/0x38
> [ 371.144594] __handle_domain_irq+0x60/0xb8
> [ 371.148820] gic_handle_irq+0xc0/0x158
> [ 371.152687] el1_irq+0xb8/0x140
> [ 371.155927] arch_cpu_idle+0x10/0x18
> [ 371.159615] do_idle+0x204/0x290
> [ 371.162943] cpu_startup_entry+0x24/0x60
> [ 371.166990] rest_init+0xb0/0xbc
> [ 371.170322] arch_call_rest_init+0xc/0x14
> [ 371.174458] start_kernel+0x404/0x430
>
> Fixes: c245d94ed106 ("i2c: iproc: Add multi byte read-write support for slave mode")
>
> Signed-off-by: Dhananjay Phadke <dphadke@linux.microsoft.com>
Applied to for-next (i.e. 5.9), thanks!
BTW my code checkers found this (unrelated to this patch):
===
CPPCHECK
drivers/i2c/busses/i2c-bcm-iproc.c:723:14: warning: Shifting signed 32-bit value by 31 bits is undefined behaviour [shiftTooManyBitsSigned]
val |= 1 << M_TX_WR_STATUS_SHIFT;
^
drivers/i2c/busses/i2c-bcm-iproc.c:741:19: warning: Shifting signed 32-bit value by 31 bits is undefined behaviour [shiftTooManyBitsSigned]
val = addr | (1 << M_TX_WR_STATUS_SHIFT);
^
===
Use the BIT macro here.
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next prev parent reply other threads:[~2020-08-12 20:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-11 0:42 [PATCH v3] i2c: iproc: fix race between client unreg and isr Dhananjay Phadke
2020-08-11 2:30 ` Florian Fainelli
2020-08-11 15:52 ` Ray Jui
2020-08-12 20:06 ` Wolfram Sang [this message]
2020-08-14 22:41 ` Ray Jui
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