4.9-stable review patch. If anyone has any objections, please let me know.
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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;