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Alexis Lothoré 030ce919e1 net: stmmac: make sure that ptp_rate is not 0 before configuring timestamping
The stmmac platform drivers that do not open-code the clk_ptp_rate value
after having retrieved the default one from the device-tree can end up
with 0 in clk_ptp_rate (as clk_get_rate can return 0). It will
eventually propagate up to PTP initialization when bringing up the
interface, leading to a divide by 0:

 Division by zero in kernel.
 CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.30-00001-g48313bd5768a #22
 Hardware name: STM32 (Device Tree Support)
 Call trace:
  unwind_backtrace from show_stack+0x18/0x1c
  show_stack from dump_stack_lvl+0x6c/0x8c
  dump_stack_lvl from Ldiv0_64+0x8/0x18
  Ldiv0_64 from stmmac_init_tstamp_counter+0x190/0x1a4
  stmmac_init_tstamp_counter from stmmac_hw_setup+0xc1c/0x111c
  stmmac_hw_setup from __stmmac_open+0x18c/0x434
  __stmmac_open from stmmac_open+0x3c/0xbc
  stmmac_open from __dev_open+0xf4/0x1ac
  __dev_open from __dev_change_flags+0x1cc/0x224
  __dev_change_flags from dev_change_flags+0x24/0x60
  dev_change_flags from ip_auto_config+0x2e8/0x11a0
  ip_auto_config from do_one_initcall+0x84/0x33c
  do_one_initcall from kernel_init_freeable+0x1b8/0x214
  kernel_init_freeable from kernel_init+0x24/0x140
  kernel_init from ret_from_fork+0x14/0x28
 Exception stack(0xe0815fb0 to 0xe0815ff8)

Prevent this division by 0 by adding an explicit check and error log
about the actual issue. While at it, remove the same check from
stmmac_ptp_register, which then becomes duplicate

Fixes: 19d857c903 ("stmmac: Fix calculations for ptp counters when clock input = 50Mhz.")
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Reviewed-by: Yanteng Si <si.yanteng@linux.dev>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20250529-stmmac_tstamp_div-v4-1-d73340a794d5@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-30 19:33:28 -07:00
arch bpf-next-6.16 2025-05-28 15:52:42 -07:00
block cgroup: Changes for v6.16 2025-05-27 20:59:53 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
Documentation bpf-next-6.16 2025-05-28 15:52:42 -07:00
drivers net: stmmac: make sure that ptp_rate is not 0 before configuring timestamping 2025-05-30 19:33:28 -07:00
fs Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
include bpf-next-6.16 2025-05-28 15:52:42 -07:00
init hardening updates for v6.16-rc1 2025-05-28 07:47:10 -07:00
io_uring Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
ipc VFS: rename lookup_one_len family to lookup_noperm and remove permission check 2025-04-08 11:24:36 +02:00
kernel bpf-next-6.16 2025-05-28 15:52:42 -07:00
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LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
net hv_netvsc: fix potential deadlock in netvsc_vf_setxdp() 2025-05-30 19:31:25 -07:00
rust Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
samples Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
scripts bpf-next-6.16 2025-05-28 15:52:42 -07:00
security Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
sound sound updates for 6.16-rc1 2025-05-27 15:05:18 -07:00
tools bpf-next-6.16 2025-05-28 15:52:42 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt ARM: 2025-04-08 13:47:55 -07:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +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 MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap NFSD 6.16 Release Notes 2025-05-28 12:21:12 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.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: update SLAB ALLOCATOR maintainers 2025-04-17 20:10:06 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Networking changes for 6.16. 2025-05-28 15:24:36 -07:00
Makefile A moderately busy cycle for documentation this time around: 2025-05-27 11:22:19 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.