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e0f9e2afd4
When using a cmdline such as "bportals=s0 qportals=s0", Linux is given a
single QMan and a single BMan portal which is shared among all CPUs, and
accessed with locking.
This is only supported for the staging SDK QBMan driver and not for the
upstream variant.
In a strange twist of events, qman_create_affine_slave() also sets
affine_portals[] for CPUs which use the portal affine to a different CPU
(aka "slaves" here), and just have portal->sharing_redirect set to that
other portal.
But that panics the kernel hard, because these dummy portals, not
having been created by qman_create_portal(), have uninitialized struct
qm_portal :: addr, eqcr, dqrr, etc, but also portal->config. So any time
these are dereferenced, the kernel panics.
There are actually 2 code paths which are in this situation:
qman_enable_irqs()
-> qm_isr_status_clear()
-> __qm_isr_write()
-> __qm_out(&portal->addr, ...) // portal->addr uninitialized
qm_shutdown_fq()
-> qm_get_portal_for_channel()
-> qman_p_get_portal_config()
-> &p->config->public_cfg // p->config uninitialized
Both functions were actually copied over from the upstream QBMan driver
(for the purpose of kexec support), which does not support portal
sharing and thus the problem does not exist there.
Actually, we need to take into consideration in these code paths only
those affine portals created by qman_create_affine_portal(), and not the
fake ones with sharing_redirect. The qman_create_affine_portal() sets
the CPU in the &affine_mask retrievable through qman_affine_cpus().
This is also the way in which dpaa_eth_add_channel() from
drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_common.c avoids the
fake channels, when dereferencing the affine_cpus[] array through the
qman_get_affine_portal() API method.
Fixes:
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||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| MAINTAINERS.NXP | ||
| Makefile | ||
| 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.