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linux/drivers/misc
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Andrew Donnellan 53d43706f2 cxl: fix nested locking hang during EEH hotplug 
commit 171ed0fcd8 upstream.

Commit 14a3ae34bf ("cxl: Prevent read/write to AFU config space while AFU
not configured") introduced a rwsem to fix an invalid memory access that
occurred when someone attempts to access the config space of an AFU on a
vPHB whilst the AFU is deconfigured, such as during EEH recovery.

It turns out that it's possible to run into a nested locking issue when EEH
recovery fails and a full device hotplug is required.
cxl_pci_error_detected() deconfigures the AFU, taking a writer lock on
configured_rwsem. When EEH recovery fails, the EEH code calls
pci_hp_remove_devices() to remove the device, which in turn calls
cxl_remove() -> cxl_pci_remove_afu() -> pci_deconfigure_afu(), which tries
to grab the writer lock that's already held.

Standard rwsem semantics don't express what we really want to do here and
don't allow for nested locking. Fix this by replacing the rwsem with an
atomic_t which we can control more finely. Allow the AFU to be locked
multiple times so long as there are no readers.

Fixes: 14a3ae34bf ("cxl: Prevent read/write to AFU config space while AFU not configured")
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2017-03-15 10:02:42 +08:00
..
altera-stapl drivers/misc/altera-stapl/altera.c: remove extraneous KERN_INFO prefix 2015-06-25 17:00:38 -07:00
c2port misc: c2port: use kobj_to_dev() 2016-02-07 23:01:45 -08:00
cb710 mmc: cb710: drop free_irq for devm_request_irq allocated irq 2013-09-26 13:55:30 -07:00
cxl cxl: fix nested locking hang during EEH hotplug 2017-03-15 10:02:42 +08:00
echo staging: echo: move to drivers/misc/ 2014-02-28 14:08:42 -08:00
eeprom Merge branch 'i2c/for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2016-10-07 14:12:21 -07:00
genwqe GenWQE: Fix bad page access during abort of resource allocation 2016-10-28 08:25:18 -04:00
ibmasm fs: Replace CURRENT_TIME with current_time() for inode timestamps 2016-09-27 21:06:21 -04:00
lis3lv02d misc: apds990x, bh1770glc, lis3lv02d: use to_i2c_client 2016-02-07 23:01:45 -08:00
mei mei: remove support for broken parallel read 2017-03-12 06:41:46 +01:00
mic mm: replace get_user_pages() write/force parameters with gup_flags 2016-10-19 08:11:43 -07:00
sgi-gru drivers/misc/sgi-gru/grumain.c: remove bogus 0x prefix from printk 2016-10-27 18:43:43 -07:00
sgi-xp mm: rename alloc_pages_exact_node() to __alloc_pages_node() 2015-09-08 15:35:28 -07:00
ti-st drivers: misc: ti-st: Use int instead of fuzzy char for callback status 2016-07-17 19:59:26 +02:00
vmw_vmci VMCI: Doorbell create and destroy fixes 2016-10-28 08:26:21 -04:00
ad525x_dpot-i2c.c misc: ad525x_dpot: Remove unnecessary MODULE_ALIAS() 2015-09-20 19:33:29 -07:00
ad525x_dpot-spi.c spi: Drop owner assignment from spi_drivers 2015-10-28 10:30:17 +09:00
ad525x_dpot.c misc: ad525x_dpot: Fix the enabling of the "otpXen" attributes 2016-03-01 16:55:13 -08:00
ad525x_dpot.h Merge branch 'char-misc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc 2012-01-09 12:08:59 -08:00
apds990x.c misc: apds990x, bh1770glc, lis3lv02d: use to_i2c_client 2016-02-07 23:01:45 -08:00
apds9802als.c drivers/misc: delete non-required instances of include <linux/init.h> 2014-02-07 15:10:19 -08:00
arm-charlcd.c drivers/misc: make arm-charlcd.c explicitly non-modular 2016-02-07 23:01:45 -08:00
atmel-ssc.c ASoC: atmel_ssc_dai: distinguish the different SSC 2016-03-02 23:43:11 +09:00
atmel_tclib.c misc: atmel_tclib: get and use slow clock 2015-10-06 12:33:14 +02:00
bh1770glc.c misc: apds990x, bh1770glc, lis3lv02d: use to_i2c_client 2016-02-07 23:01:45 -08:00
cs5535-mfgpt.c misc: drop owner assignment from platform_drivers 2014-10-20 16:20:54 +02:00
ds1682.c misc: ds1682: clean up ds1682_eeprom_read() and ds1682_eeprom_write() 2015-08-05 13:53:39 -07:00
dummy-irq.c Add MODULE_DESCRIPTION to dummy-irq.c and lkdtm.c in drivers/misc 2014-07-09 14:19:34 -07:00
enclosure.c enclosure: fix WARN_ON removing an adapter in multi-path devices 2015-03-31 08:53:36 +03:00
fsa9480.c treewide: fix comments and printk msgs 2014-01-07 15:06:07 +01:00
hmc6352.c drivers/misc: delete non-required instances of include <linux/init.h> 2014-02-07 15:10:19 -08:00
hpilo.c drivers/misc/hpilo: Changes to support new security states in iLO5 FW 2016-09-27 12:53:46 +02:00
hpilo.h misc: hpilo: increase number of max supported channels 2012-06-14 17:22:12 -07:00
ics932s401.c hwmon: Change my email address. 2013-08-27 08:28:01 -07:00
ioc4.c misc: ioc4: simplify wave period measurement in clock_calibrate 2015-01-12 05:04:11 -08:00
isl29003.c misc: Drop owner assignment from i2c_driver 2015-08-10 08:37:35 +02:00
isl29020.c drivers/misc: delete non-required instances of include <linux/init.h> 2014-02-07 15:10:19 -08:00
Kconfig Merge 4.8-rc5 into char-misc-next 2016-09-05 08:04:07 +02:00
kgdbts.c drivers/misc: make kgdbts.c slightly more explicitly non-modular 2015-09-20 19:32:35 -07:00
lattice-ecp3-config.c spi: Drop owner assignment from spi_drivers 2015-10-28 10:30:17 +09:00
lkdtm.h lkdtm: silence warnings about function declarations 2016-07-15 16:14:45 -07:00
lkdtm_bugs.c lkdtm: silence warnings about function declarations 2016-07-15 16:14:45 -07:00
lkdtm_core.c lkdtm: silence warnings about function declarations 2016-07-15 16:14:45 -07:00
lkdtm_heap.c lkdtm: silence warnings about function declarations 2016-07-15 16:14:45 -07:00
lkdtm_perms.c lkdtm: silence warnings about function declarations 2016-07-15 16:14:45 -07:00
lkdtm_rodata.c lkdtm: Mark lkdtm_rodata_do_nothing() notrace 2016-08-31 13:12:38 +02:00
lkdtm_usercopy.c lkdtm: adjust usercopy tests to bypass const checks 2016-09-06 12:17:30 -07:00
Makefile Merge 4.8-rc5 into char-misc-next 2016-09-05 08:04:07 +02:00
panel.c misc: panel, convert struct to bitmap 2016-02-11 19:24:23 -08:00
pch_phub.c misc: pch_phub: Add UART_CLK quirk for Boston platform 2016-08-31 15:45:18 +02:00
phantom.c misc: phantom: remove deprecated IRQF_DISABLED 2013-10-16 12:36:10 -07:00
pti.c misc: pti: remove unnecessary pci_set_drvdata() 2013-09-26 09:13:54 -07:00
qcom-coincell.c ARM: qcom: silence an uninitialized variable warning 2016-05-01 14:20:04 -07:00
spear13xx_pcie_gadget.c spear13xx_pcie_gadget: use per-attribute show and store methods 2015-10-13 22:17:40 -07:00
sram.c misc: sram: fix check of devm_ioremap*() return value 2016-04-30 14:15:56 -07:00
ti_dac7512.c spi: Drop owner assignment from spi_drivers 2015-10-28 10:30:17 +09:00
tifm_7xx1.c misc: tifm: match return type of wait_for_completion_timeout 2015-03-25 11:36:38 +01:00
tifm_core.c tifm: convert bus code to use dev_groups 2013-10-16 18:40:58 -07:00
tsl2550.c misc: Drop owner assignment from i2c_driver 2015-08-10 08:37:35 +02:00
vexpress-syscfg.c ARM: vexpress: Remove non-DT code 2014-11-28 16:08:16 +01:00
vmw_balloon.c mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM 2015-11-06 17:50:42 -08:00