This is a note to let you know that I've just added the patch titled

scsi: aacraid: Prevent crash in case of free interrupt during scsi EH path

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: scsi-aacraid-prevent-crash-in-case-of-free-interrupt-during-scsi-eh-path.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 14:00:34 CET 2018

From: "Guilherme G. Piccoli" gpiccoli@linux.vnet.ibm.com Date: Fri, 17 Nov 2017 19:14:55 -0200 Subject: scsi: aacraid: Prevent crash in case of free interrupt during scsi EH path

From: "Guilherme G. Piccoli" gpiccoli@linux.vnet.ibm.com

[ Upstream commit e4717292ddebcfe231651b5aff9fa19ca158d178 ]

As part of the scsi EH path, aacraid performs a reinitialization of the adapter, which encompass freeing resources and IRQs, NULLifying lots of pointers, and then initialize it all over again. We've identified a problem during the free IRQ portion of this path if CONFIG_DEBUG_SHIRQ is enabled on kernel config file.

Happens that, in case this flag was set, right after free_irq() effectively clears the interrupt, it checks if it was requested as IRQF_SHARED. In positive case, it performs another call to the IRQ handler on driver. Problem is: since aacraid currently free some resources *before* freeing the IRQ, once free_irq() path calls the handler again (due to CONFIG_DEBUG_SHIRQ), aacraid crashes due to NULL pointer dereference with the following trace:

aac_src_intr_message+0xf8/0x740 [aacraid] __free_irq+0x33c/0x4a0 free_irq+0x78/0xb0 aac_free_irq+0x13c/0x150 [aacraid] aac_reset_adapter+0x2e8/0x970 [aacraid] aac_eh_reset+0x3a8/0x5d0 [aacraid] scsi_try_host_reset+0x74/0x180 scsi_eh_ready_devs+0xc70/0x1510 scsi_error_handler+0x624/0xa20

This patch prevents the crash by changing the order of the deinitialization in this path of aacraid: first we clear the IRQ, then we free other resources. No functional change intended.

Signed-off-by: Guilherme G. Piccoli gpiccoli@linux.vnet.ibm.com Reviewed-by: Raghava Aditya Renukunta RaghavaAditya.Renukunta@microsemi.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/scsi/aacraid/commsup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/scsi/aacraid/commsup.c +++ b/drivers/scsi/aacraid/commsup.c @@ -1416,13 +1416,13 @@ static int _aac_reset_adapter(struct aac * will ensure that i/o is queisced and the card is flushed in that * case. */ + aac_free_irq(aac); aac_fib_map_free(aac); pci_free_consistent(aac->pdev, aac->comm_size, aac->comm_addr, aac->comm_phys); aac->comm_addr = NULL; aac->comm_phys = 0; kfree(aac->queues); aac->queues = NULL; - aac_free_irq(aac); kfree(aac->fsa_dev); aac->fsa_dev = NULL; quirks = aac_get_driver_ident(index)->quirks;

Patches currently in stable-queue which might be from gpiccoli@linux.vnet.ibm.com are

queue-4.9/scsi-aacraid-prevent-crash-in-case-of-free-interrupt-during-scsi-eh-path.patch