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Niklas Schnelle 31a7dc5a24 s390/pci: Allow re-add of a reserved but not yet removed device 
commit 4b1815a52d upstream.

The architecture assumes that PCI functions can be removed synchronously
as PCI events are processed. This however clashes with the reference
counting of struct pci_dev which allows device drivers to hold on to a
struct pci_dev reference even as the underlying device is removed. To
bridge this gap commit 2a671f77ee ("s390/pci: fix use after free of
zpci_dev") keeps the struct zpci_dev in ZPCI_FN_STATE_RESERVED state
until common code releases the struct pci_dev. Only when all references
are dropped, the struct zpci_dev can be removed and freed.

Later commit a46044a92a ("s390/pci: fix zpci_zdev_put() on reserve")
moved the deletion of the struct zpci_dev from the zpci_list in
zpci_release_device() to the point where the device is reserved. This
was done to prevent handling events for a device that is already being
removed, e.g. when the platform generates both PCI event codes 0x304
and 0x308. In retrospect, deletion from the zpci_list in the release
function without holding the zpci_list_lock was also racy.

A side effect of this handling is that if the underlying device
re-appears while the struct zpci_dev is in the ZPCI_FN_STATE_RESERVED
state, the new and old instances of the struct zpci_dev and/or struct
pci_dev may clash. For example when trying to create the IOMMU sysfs
files for the new instance. In this case, re-adding the new instance is
aborted. The old instance is removed, and the device will remain absent
until the platform issues another event.

Fix this by allowing the struct zpci_dev to be brought back up right
until it is finally removed. To this end also keep the struct zpci_dev
in the zpci_list until it is finally released when all references have
been dropped.

Deletion from the zpci_list from within the release function is made
safe by using kref_put_lock() with the zpci_list_lock. This ensures that
the releasing code holds the last reference.

Cc: stable@vger.kernel.org
Fixes: a46044a92a ("s390/pci: fix zpci_zdev_put() on reserve")
Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
Tested-by: Gerd Bayer <gbayer@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-06-27 11:11:14 +01:00
arch
block block: don't use submit_bio_noacct_nocheck in blk_zone_wplug_bio_work 2025-06-19 15:32:33 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Redo lookup on EEXIST 2025-06-19 15:31:30 +02:00
Documentation regulator: dt-bindings: mt6357: Drop fixed compatible requirement 2025-06-19 15:32:37 +02:00
drivers s390/pci: Prevent self deletion in disable_slot() 2025-06-27 11:11:14 +01:00
fs gfs2: move msleep to sleepable context 2025-06-27 11:11:12 +01:00
include overflow: Introduce __DEFINE_FLEX for having no initializer 2025-06-19 15:32:37 +02:00
init rust: clean Rust 1.88.0's unnecessary_transmutes lint 2025-05-18 08:24:51 +02:00
io_uring io_uring/kbuf: account ring io_buffer_list memory 2025-06-27 11:11:14 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel ring-buffer: Move cpus_read_lock() outside of buffer->mutex 2025-06-19 15:32:36 +02:00
lib iov_iter: use iov_offset for length calculation in iov_iter_aligned_bvec 2025-06-19 15:32:21 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm page_pool: Move pp_magic check into helper functions 2025-06-19 15:31:42 +02:00
net calipso: unlock rcu before returning -EAFNOSUPPORT 2025-06-19 15:32:37 +02:00
rust rust: alloc: add missing invariant in Vec::set_len() 2025-06-19 15:32:09 +02:00
samples samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora 2025-05-29 11:02:01 +02:00
scripts randstruct: gcc-plugin: Fix attribute addition 2025-06-19 15:32:04 +02:00
security smack: Revert "smackfs: Added check catlen" 2025-05-29 11:02:48 +02:00
sound ASoC: amd: sof_amd_sdw: Fix unlikely uninitialized variable use in create_sdw_dailinks() 2025-06-27 11:11:13 +01:00
tools tools/resolve_btfids: Fix build when cross compiling kernel with clang. 2025-06-19 15:32:33 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Add member to struct kvm_gfn_range to indicate private/shared 2025-05-22 14:29:36 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-18 08:24:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.34 2025-06-19 15:32:38 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.