kernel/linux.git/include/asm-generic/codetag.lds.h, branch v6.19.11

codetag: avoid unused alloc_tags sections/symbols

2025-07-10T05:42:14+00:00

With CONFIG_MEM_ALLOC_PROFILING=n, vmlinux and all modules unnecessarily contain the symbols __start_alloc_tags and __stop_alloc_tags, which define an empty range. In the case of modules, the presence of these symbols also forces the linker to create an empty .codetag.alloc_tags section. Update codetag.lds.h to make the data conditional on CONFIG_MEM_ALLOC_PROFILING. Link: https://lkml.kernel.org/r/20250618125037.53182-1-petr.pavlu@suse.com Signed-off-by: Petr Pavlu Reviewed-by: Kent Overstreet Reviewed-by: Suren Baghdasaryan Cc: Arnd Bergmann Cc: Casey Chen Cc: Petr Pavlu Signed-off-by: Andrew Morton

alloc_tag: remove empty module tag section

2025-07-10T05:42:03+00:00

The empty MOD_CODETAG_SECTIONS() macro added an incomplete .data section in module linker script, which caused symbol lookup tools like gdb to misinterpret symbol addresses e.g., __ib_process_cq incorrectly mapping to unrelated functions like below. (gdb) disas __ib_process_cq Dump of assembler code for function trace_event_fields_cq_schedule: Removing the empty section restores proper symbol resolution and layout, ensuring .data placement behaves as expected. Link: https://lkml.kernel.org/r/20250610162258.324645-1-cachen@purestorage.com Fixes: 0db6f8d7820a ("alloc_tag: load module tags into separate contiguous memory") 22d407b164ff ("lib: add allocation tagging support for memory allocation profiling") Signed-off-by: Casey Chen Reviewed-by: Yuanyuan Zhong Acked-by: Suren Baghdasaryan Cc: Arnd Bergmann Cc: Kent Overstreet Cc: Luis Chamberalin Cc: Pasha Tatashin Signed-off-by: Andrew Morton

alloc_tag: load module tags into separate contiguous memory

2024-11-07T22:25:16+00:00

When a module gets unloaded there is a possibility that some of the allocations it made are still used and therefore the allocation tags corresponding to these allocations are still referenced. As such, the memory for these tags can't be freed. This is currently handled as an abnormal situation and module's data section is not being unloaded. To handle this situation without keeping module's data in memory, allow codetags with longer lifespan than the module to be loaded into their own separate memory. The in-use memory areas and gaps after module unloading in this separate memory are tracked using maple trees. Allocation tags arrange their separate memory so that it is virtually contiguous and that will allow simple allocation tag indexing later on in this patchset. The size of this virtually contiguous memory is set to store up to 100000 allocation tags. [surenb@google.com: fix empty codetag module section handling] Link: https://lkml.kernel.org/r/20241101000017.3856204-1-surenb@google.com [akpm@linux-foundation.org: update comment, per Dan] Link: https://lkml.kernel.org/r/20241023170759.999909-4-surenb@google.com Signed-off-by: Suren Baghdasaryan Reviewed-by: Pasha Tatashin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Borislav Petkov (AMD) Cc: Christoph Hellwig Cc: Daniel Gomez Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: David Rientjes Cc: Dennis Zhou Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joonsoo Kim Cc: Kalesh Singh Cc: Kees Cook Cc: Kent Overstreet Cc: Liam R. Howlett Cc: Luis Chamberlain Cc: Matthew Wilcox Cc: Michal Hocko Cc: Mike Rapoport (Microsoft) Cc: Minchan Kim Cc: Paul E. McKenney Cc: Petr Pavlu Cc: Roman Gushchin Cc: Sami Tolvanen Cc: Sourav Panda Cc: Steven Rostedt (Google) Cc: Thomas Gleixner Cc: Thomas Huth Cc: Uladzislau Rezki (Sony) Cc: Vlastimil Babka Cc: Xiongwei Song Cc: Yu Zhao Cc: Dan Carpenter Signed-off-by: Andrew Morton

lib: add allocation tagging support for memory allocation profiling

2024-04-26T03:55:52+00:00

Introduce CONFIG_MEM_ALLOC_PROFILING which provides definitions to easily instrument memory allocators. It registers an "alloc_tags" codetag type with /proc/allocinfo interface to output allocation tag information when the feature is enabled. CONFIG_MEM_ALLOC_PROFILING_DEBUG is provided for debugging the memory allocation profiling instrumentation. Memory allocation profiling can be enabled or disabled at runtime using /proc/sys/vm/mem_profiling sysctl when CONFIG_MEM_ALLOC_PROFILING_DEBUG=n. CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT enables memory allocation profiling by default. [surenb@google.com: Documentation/filesystems/proc.rst: fix allocinfo title] Link: https://lkml.kernel.org/r/20240326073813.727090-1-surenb@google.com [surenb@google.com: do limited memory accounting for modules with ARCH_NEEDS_WEAK_PER_CPU] Link: https://lkml.kernel.org/r/20240402180933.1663992-2-surenb@google.com [klarasmodin@gmail.com: explicitly include irqflags.h in alloc_tag.h] Link: https://lkml.kernel.org/r/20240407133252.173636-1-klarasmodin@gmail.com [surenb@google.com: fix alloc_tag_init() to prevent passing NULL to PTR_ERR()] Link: https://lkml.kernel.org/r/20240417003349.2520094-1-surenb@google.com Link: https://lkml.kernel.org/r/20240321163705.3067592-14-surenb@google.com Signed-off-by: Suren Baghdasaryan Co-developed-by: Kent Overstreet Signed-off-by: Kent Overstreet Signed-off-by: Klara Modin Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton