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Filename Latest commit message Latest commit date
Lukas Wunner 464da38ba8 PCI: pciehp: Fix infinite loop in IRQ handler upon power fault
commit 23584c1ed3e15a6f4bfab8dc5a88d94ab929ee12 upstream.

The Power Fault Detected bit in the Slot Status register differs from
all other hotplug events in that it is sticky:  It can only be cleared
after turning off slot power.  Per PCIe r5.0, sec. 6.7.1.8:

  If a power controller detects a main power fault on the hot-plug slot,
  it must automatically set its internal main power fault latch [...].
  The main power fault latch is cleared when software turns off power to
  the hot-plug slot.

The stickiness used to cause interrupt storms and infinite loops which
were fixed in 2009 by commits 5651c48cfa ("PCI pciehp: fix power fault
interrupt storm problem") and 99f0169c17 ("PCI: pciehp: enable
software notification on empty slots").

Unfortunately in 2020 the infinite loop issue was inadvertently
reintroduced by commit 8edf5332c393 ("PCI: pciehp: Fix MSI interrupt
race"):  The hardirq handler pciehp_isr() clears the PFD bit until
pciehp's power_fault_detected flag is set.  That happens in the IRQ
thread pciehp_ist(), which never learns of the event because the hardirq
handler is stuck in an infinite loop.  Fix by setting the
power_fault_detected flag already in the hardirq handler.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=214989
Link: https://lore.kernel.org/linux-pci/DM8PR11MB5702255A6A92F735D90A4446868B9@DM8PR11MB5702.namprd11.prod.outlook.com
Fixes: 8edf5332c393 ("PCI: pciehp: Fix MSI interrupt race")
Link: https://lore.kernel.org/r/66eaeef31d4997ceea357ad93259f290ededecfd.1637187226.git.lukas@wunner.de
Reported-by: Joseph Bao <joseph.bao@intel.com>
Tested-by: Joseph Bao <joseph.bao@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v4.19+
Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-05 12:35:36 +01:00
arch powerpc/32: Fix boot failure with GCC latent entropy plugin 2022-02-01 17:24:36 +01:00
block block: Fix wrong offset in bio_truncate() 2022-02-01 17:24:39 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation dt-bindings: can: tcan4x5x: fix mram-cfg RX FIFO config 2022-02-01 17:24:39 +01:00
drivers PCI: pciehp: Fix infinite loop in IRQ handler upon power fault 2022-02-05 12:35:36 +01:00
fs fsnotify: invalidate dcache before IN_DELETE event 2022-02-01 17:24:39 +01:00
include fsnotify: invalidate dcache before IN_DELETE event 2022-02-01 17:24:39 +01:00
init
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel tracing: Don't inc err_log entry count if entry allocation fails 2022-02-01 17:24:34 +01:00
lib lib/test_meminit: destroy cache in kmem_cache_alloc_bulk() test 2022-01-27 09:19:55 +01:00
LICENSES
mm shmem: fix a race between shmem_unused_huge_shrink and shmem_evict_inode 2022-01-27 09:19:29 +01:00
net ipv4: tcp: send zero IPID in SYNACK messages 2022-02-01 17:24:39 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts scripts/dtc: dtx_diff: remove broken example from help text 2022-01-27 09:19:55 +01:00
security selinux: fix potential memleak in selinux_add_opt() 2022-01-27 09:19:35 +01:00
sound ASoC: mediatek: mt8173: fix device_node leak 2022-01-27 09:19:48 +01:00
tools perf script: Fix hex dump character output 2022-01-27 09:19:54 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
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Makefile Linux 5.4.176 2022-02-01 17:24:40 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.