Date: Mon, 1 Jun 1998 13:07:25 -0700 (PDT) From: nick.hibma@jrc.it To: freebsd-gnats-submit@FreeBSD.ORG Subject: kern/6819: pci_unmap_int (pci/pci.c) does not properly unmask an interrupt Message-ID: <199806012007.NAA20243@hub.freebsd.org>
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>Number: 6819 >Category: kern >Synopsis: pci_unmap_int (pci/pci.c) does not properly unmask an interrupt >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Jun 1 13:10:00 PDT 1998 >Last-Modified: >Originator: Nick Hibma >Organization: None >Release: 2.2.1 >Environment: FreeBSD heidi.plazza.it 2.2.1-RELEASE FreeBSD 2.2.1-RELEASE #48: Mon Jun 1 20:37:12 CEST 1998 toor@heidi.plazza.it:/usr/src/sys/compile/HEIDI i386 >Description: Unmapping an interrupt used by a PCI device is incorrectly done. Mapping it, unmapping it and then mapping it again results it a failing mapping. Unmapping is done, but somehow the unmapping is not done completely in pci_unmap_int. After the failed attempt the to map the interrupt another try is succesfull: pci_map_int (succesfull) pci_unmap_int (succesfull) pci_map_int (fails) pci_map_int (succesfull) <<<<<<<<<<<<<<<<<<<< pci_unmap_int (succesfull) pci_map_int (fails) pci_map_int (succesfull) <<<<<<<<<<<<<<<<<<<< etc. >How-To-Repeat: Load an LKM module that registers a PCI interrupt with pci_map_int and can be unloaded unmapping the interrupt with pci_unmap_int. Load the LKM, unload it and load it again. The LKM should complain about not being able to map the interrupt. Loading it a second time should be succesfull. Possible LKM to be used: USB stack http://www.etla.net/~n_hibma/usb/usb.pl This LKM maps the interrupt as bio_imask. >Fix: Moved the exclusion of the interrupt mask below the part detaching the irq. Reason for this is that in pci_imask_exclude the interrupt is masked out but after calling update_intr_masks the bit is set again in *maskptr, because the interrupt has not yet been detached. This fix should be checked by someone who knows what he is doing, when interrupts are concerned, because I am a nono in that field (any field actually, but don't tell anyone :-). diff -C3 pci.c.orig pci.c *** pci.c.orig Mon Jun 1 21:59:24 1998 --- pci.c Mon Jun 1 21:55:35 1998 *************** *** 1392,1397 **** --- 1392,1399 ---- if (irq == 0xff) return (0); + oldspl = splq (1ul << irq); + /* ** Search and unlink interrupt descriptor. */ *************** *** 1415,1423 **** irq, this->pcid_handler, this->pcid_argument, this->pcid_tag.tag, this->pcid_tally); - if (!getintdescbymptr (irq, this->pcid_maskptr)) - (void) pcibus->pb_imaskexc (irq, this->pcid_maskptr); - /* ** If this irq no longer included in the mask, remove it. */ --- 1417,1422 ---- *************** *** 1437,1444 **** } else if (tail->pcid_next == NULL) { - oldspl = splq (1ul << irq); - /* ** Remove the shared int handler. ** Install the last remaining handler. --- 1436,1441 ---- *************** *** 1455,1465 **** if (result) printf ("\tirq %d: cannot install handler.\n", irq); - - splx (oldspl); }; free (this, M_DEVBUF); return (1); } --- 1452,1464 ---- if (result) printf ("\tirq %d: cannot install handler.\n", irq); }; + if (!getintdescbymptr (irq, this->pcid_maskptr)) + (void) pcibus->pb_imaskexc (irq, this->pcid_maskptr); + free (this, M_DEVBUF); + splx (oldspl); return (1); } >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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