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From: Jim Cromie <jim.cromie@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>, Jason Baron <jbaron@akamai.com>,
	 Luis Chamberlain <mcgrof@kernel.org>,
	Petr Pavlu <petr.pavlu@suse.com>,
	 Daniel Gomez <da.gomez@kernel.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	 Aaron Tomlin <atomlin@atomlin.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	 linux-modules@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	 Jim Cromie <jim.cromie@gmail.com>,
	 Louis Chauvet <louis.chauvet@bootlin.com>
Subject: [PATCH v4 0/5] fix section alignment on i386 when CONFIG_DRM_USE_DYNAMIC_DEBUG=Y
Date: Tue, 30 Jun 2026 12:37:49 -0600	[thread overview]
Message-ID: <20260630-fix-align-v4-0-42e6ec883342@gmail.com> (raw)

This fixes a section misalignement on i386, when CONFIG_DRM=y and
CONFIG_DRM_USE_DYNAMIC_DEBUG=Y

In this config, the __dyndbg_classes section gets a single
struct/record.  On i386 this is 28-bytes, breaking the required
ALIGN(8) on the following __dyndbg section.

This breaks dynamic_debug_init() with a NULL pointer dereference; the
section traversal logic encounters padding bytes instead of a valid
descriptor.

the series:

1. moves BOUNDED_SECTION_* macros from vmlinux.lds.h to its own file.
   v2- adds note that macros are for vmlinux.lds.h only, not for modules.

2. drops unused HEADERED_SECTION_* macros from that new file

3. adds ALIGN(8) into BOUNDED_SECTION* macros
   omission causing NULL ptr on i386
   adds,uses BOUNDED_SECTION _ALIGNED variants

4. removes now redundant ALIGN(8)s in vmlinux.lds.h

5. adds dyndbg.lds.S to KEEP sections in modules
   follows codetag.lds.h model

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v3:
- move #includes to top of files,
- drop redundant ALIGN(8) in dydnbg.lds.S: DYNDBG_SECTIONS macro
- add Reviewed-by tag (thx Petr)

v2:
- avoid BOUNDED_SECTION in modules, dont need _start & _end symbols.
- sets 0 address to the sections, not just whatever current is.

---
Jim Cromie (5):
      vmlinux.lds.h: refactor BOUNDED_SECTION_* macros into bounded_sections.lds.h
      vmlinux.lds.h: drop unused HEADERED_SECTION* macros
      vmlinux.lds.h: Fix ALIGN(8) omission causing NULL ptr on i386
      vmlinux.lds.h: remove redundant ALIGN(8) directives
      dyndbg.lds.S: fix lost dyndbg sections in modules

 MAINTAINERS                                |  1 +
 include/asm-generic/bounded_sections.lds.h | 32 ++++++++++++++
 include/asm-generic/dyndbg.lds.h           | 18 ++++++++
 include/asm-generic/vmlinux.lds.h          | 68 ++++++------------------------
 scripts/module.lds.S                       |  2 +
 5 files changed, 66 insertions(+), 55 deletions(-)
---
base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
change-id: 20260630-fix-align-589738662161

Best regards,
-- 
Jim Cromie <jim.cromie@gmail.com>


             reply	other threads:[~2026-06-30 18:38 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-30 18:37 Jim Cromie [this message]
2026-06-30 18:37 ` [PATCH v4 1/5] vmlinux.lds.h: refactor BOUNDED_SECTION_* macros into bounded_sections.lds.h Jim Cromie
2026-06-30 18:37 ` [PATCH v4 2/5] vmlinux.lds.h: drop unused HEADERED_SECTION* macros Jim Cromie
2026-06-30 18:37 ` [PATCH v4 3/5] vmlinux.lds.h: Fix ALIGN(8) omission causing NULL ptr on i386 Jim Cromie
2026-06-30 18:37 ` [PATCH v4 4/5] vmlinux.lds.h: remove redundant ALIGN(8) directives Jim Cromie
2026-06-30 18:37 ` [PATCH v4 5/5] dyndbg.lds.S: fix lost dyndbg sections in modules Jim Cromie

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