Commit Graph
46 Commits
Author SHA1 Message Date
Harry Yoo (Oracle)andVlastimil Babka (SUSE) a37b0066a1 lib/alloc_tag: introduce mem_alloc_profiling_permanently_disabled()
mem_alloc_profiling_enabled() tells whether memalloc profiling is
currently enabled. However, even when this function returns false,
it can be enabled later.

However, this is not enough. Some optimizations can be applied only when
memalloc profiling is permanently disabled. For example, to skip the
creation of KMALLOC_NO_OBJ_EXT caches at boot time, mem_profiling must
be set to "never", "0" w/ debugging on, or have been shutdown so that
it can no longer be enabled.

Introduce mem_alloc_profiling_permanently_disabled() for this purpose.

Signed-off-by: Harry Yoo (Oracle) <harry@kernel.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Link: https://patch.msgid.link/20260713-kmalloc-no-objext-v3-3-47c7bd138de7@kernel.org
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
2026-07-14 16:44:40 +02:00
Bart Van AsscheandAndrew Morton 67c2696cf7 lib: split codetag_lock_module_list()
Letting a function argument indicate whether a lock or unlock operation
should be performed is incompatible with compile-time analysis of locking
operations by sparse and Clang.  Hence, split codetag_lock_module_list()
into two functions: a function that locks cttype->mod_lock and another
function that unlocks cttype->mod_lock.  No functionality has been
changed.  See also commit 916cc5167c ("lib: code tagging framework").

Link: https://lore.kernel.org/20260324214226.3684605-1-bvanassche@acm.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21 11:31:28 -07:00
Hao GeandAndrew Morton 2956268efc alloc_tag: fix use-after-free in /proc/allocinfo after module unload
allocinfo_start() only reinitializes the codetag iterator at position 0. 
For subsequent reads (position > 0), it reuses cached iterator state from
the previous batch.  allocinfo_stop() drops mod_lock between read batches,
which allows module unload to complete and free the module memory that the
cached iterator still references:

  CPU0 (read)                        CPU1 (rmmod)
  ----                               ----
  allocinfo_start(pos=0)
    down_read(mod_lock)
    allocinfo_show()
    ...
  allocinfo_stop()
    up_read(mod_lock)
                                     codetag_unload_module()
                                       kfree(cmod)
                                       release_module_tags()
                                     ...
                                     free_mod_mem()
  allocinfo_start(pos=N)
    down_read(mod_lock)
    // reuses cached iter, skips re-init
  allocinfo_show()
    ct->filename   <-- UAF

After free_mod_mem() frees the module's .rodata, allocinfo_show()
dereferences ct->filename, ct->function which point there.

Save the iterator state in allocinfo_next() and resume from it in
allocinfo_start() with codetag_next_ct(), which detects module removal via
idr_find() returning NULL and skips to the next module.

Link: https://lore.kernel.org/20260604065938.105991-1-hao.ge@linux.dev
Fixes: 9f44df50fe ("alloc_tag: keep codetag iterator active between read()")
Signed-off-by: Hao Ge <hao.ge@linux.dev>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21 11:31:28 -07:00
Hao GeandAndrew Morton 0c3a350d13 mm/alloc_tag: replace fixed-size early PFN array with dynamic linked list
Pages allocated before page_ext is available have their codetag left
uninitialized.  Track these early PFNs and clear their codetag in
clear_early_alloc_pfn_tag_refs() to avoid "alloc_tag was not set" warnings
when they are freed later.

Currently a fixed-size array of 8192 entries is used, with a warning if
the limit is exceeded.  However, the number of early allocations depends
on the number of CPUs and can be larger than 8192.

Replace the fixed-size array with a dynamically allocated linked list of
pfn_pool structs.  Each node is allocated via alloc_page() and mapped to a
pfn_pool containing a next pointer, an atomic slot counter, and a PFN
array that fills the remainder of the page.

The tracking pages themselves are allocated via alloc_page(), which would
trigger __pgalloc_tag_add() -> alloc_tag_add_early_pfn() and recurse
indefinitely.  Introduce __GFP_NO_CODETAG (reuses the %__GFP_NO_OBJ_EXT
bit) and pass gfp_flags through pgalloc_tag_add() so that the early path
can skip recording allocations that carry this flag.

Link: https://lore.kernel.org/20260604024008.46592-1-hao.ge@linux.dev
Signed-off-by: Hao Ge <hao.ge@linux.dev>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-21 11:31:28 -07:00
Hao GeandAndrew Morton 6b1842775a mm/alloc_tag: clear codetag for pages allocated before page_ext initialization
Due to initialization ordering, page_ext is allocated and initialized
relatively late during boot.  Some pages have already been allocated and
freed before page_ext becomes available, leaving their codetag
uninitialized.

A clear example is in init_section_page_ext(): alloc_page_ext() calls
kmemleak_alloc().  If the slab cache has no free objects, it falls back to
the buddy allocator to allocate memory.  However, at this point page_ext
is not yet fully initialized, so these newly allocated pages have no
codetag set.  These pages may later be reclaimed by KASAN, which causes
the warning to trigger when they are freed because their codetag ref is
still empty.

Use a global array to track pages allocated before page_ext is fully
initialized.  The array size is fixed at 8192 entries, and will emit a
warning if this limit is exceeded.  When page_ext initialization
completes, set their codetag to empty to avoid warnings when they are
freed later.

This warning is only observed with CONFIG_MEM_ALLOC_PROFILING_DEBUG=Y and
mem_profiling_compressed disabled:

[    9.582133] ------------[ cut here ]------------
[    9.582137] alloc_tag was not set
[    9.582139] WARNING: ./include/linux/alloc_tag.h:164 at __pgalloc_tag_sub+0x40f/0x550, CPU#5: systemd/1
[    9.582190] CPU: 5 UID: 0 PID: 1 Comm: systemd Not tainted 7.0.0-rc4 #1 PREEMPT(lazy)
[    9.582192] Hardware name: Red Hat KVM, BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[    9.582194] RIP: 0010:__pgalloc_tag_sub+0x40f/0x550
[    9.582196] Code: 00 00 4c 29 e5 48 8b 05 1f 88 56 05 48 8d 4c ad 00 48 8d 2c c8 e9 87 fd ff ff 0f 0b 0f 0b e9 f3 fe ff ff 48 8d 3d 61 2f ed 03 <67> 48 0f b9 3a e9 b3 fd ff ff 0f 0b eb e4 e8 5e cd 14 02 4c 89 c7
[    9.582197] RSP: 0018:ffffc9000001f940 EFLAGS: 00010246
[    9.582200] RAX: dffffc0000000000 RBX: 1ffff92000003f2b RCX: 1ffff110200d806c
[    9.582201] RDX: ffff8881006c0360 RSI: 0000000000000004 RDI: ffffffff9bc7b460
[    9.582202] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff3a62324
[    9.582203] R10: ffffffff9d311923 R11: 0000000000000000 R12: ffffea0004001b00
[    9.582204] R13: 0000000000002000 R14: ffffea0000000000 R15: ffff8881006c0360
[    9.582206] FS:  00007ffbbcf2d940(0000) GS:ffff888450479000(0000) knlGS:0000000000000000
[    9.582208] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    9.582210] CR2: 000055ee3aa260d0 CR3: 0000000148b67005 CR4: 0000000000770ef0
[    9.582211] PKRU: 55555554
[    9.582212] Call Trace:
[    9.582213]  <TASK>
[    9.582214]  ? __pfx___pgalloc_tag_sub+0x10/0x10
[    9.582216]  ? check_bytes_and_report+0x68/0x140
[    9.582219]  __free_frozen_pages+0x2e4/0x1150
[    9.582221]  ? __free_slab+0xc2/0x2b0
[    9.582224]  qlist_free_all+0x4c/0xf0
[    9.582227]  kasan_quarantine_reduce+0x15d/0x180
[    9.582229]  __kasan_slab_alloc+0x69/0x90
[    9.582232]  kmem_cache_alloc_noprof+0x14a/0x500
[    9.582234]  do_getname+0x96/0x310
[    9.582237]  do_readlinkat+0x91/0x2f0
[    9.582239]  ? __pfx_do_readlinkat+0x10/0x10
[    9.582240]  ? get_random_bytes_user+0x1df/0x2c0
[    9.582244]  __x64_sys_readlinkat+0x96/0x100
[    9.582246]  do_syscall_64+0xce/0x650
[    9.582250]  ? __x64_sys_getrandom+0x13a/0x1e0
[    9.582252]  ? __pfx___x64_sys_getrandom+0x10/0x10
[    9.582254]  ? do_syscall_64+0x114/0x650
[    9.582255]  ? ksys_read+0xfc/0x1d0
[    9.582258]  ? __pfx_ksys_read+0x10/0x10
[    9.582260]  ? do_syscall_64+0x114/0x650
[    9.582262]  ? do_syscall_64+0x114/0x650
[    9.582264]  ? __pfx_fput_close_sync+0x10/0x10
[    9.582266]  ? file_close_fd_locked+0x178/0x2a0
[    9.582268]  ? __x64_sys_faccessat2+0x96/0x100
[    9.582269]  ? __x64_sys_close+0x7d/0xd0
[    9.582271]  ? do_syscall_64+0x114/0x650
[    9.582273]  ? do_syscall_64+0x114/0x650
[    9.582275]  ? clear_bhb_loop+0x50/0xa0
[    9.582277]  ? clear_bhb_loop+0x50/0xa0
[    9.582279]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[    9.582280] RIP: 0033:0x7ffbbda345ee
[    9.582282] Code: 0f 1f 40 00 48 8b 15 29 38 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 0f 1f 40 00 f3 0f 1e fa 49 89 ca b8 0b 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d fa 37 0d 00 f7 d8 64 89 01 48
[    9.582284] RSP: 002b:00007ffe2ad8de58 EFLAGS: 00000202 ORIG_RAX: 000000000000010b
[    9.582286] RAX: ffffffffffffffda RBX: 000055ee3aa25570 RCX: 00007ffbbda345ee
[    9.582287] RDX: 000055ee3aa25570 RSI: 00007ffe2ad8dee0 RDI: 00000000ffffff9c
[    9.582288] RBP: 0000000000001000 R08: 0000000000000003 R09: 0000000000001001
[    9.582289] R10: 0000000000001000 R11: 0000000000000202 R12: 0000000000000033
[    9.582290] R13: 00007ffe2ad8dee0 R14: 00000000ffffff9c R15: 00007ffe2ad8deb0
[    9.582292]  </TASK>
[    9.582293] ---[ end trace 0000000000000000 ]---

Link: https://lore.kernel.org/20260331081312.123719-1-hao.ge@linux.dev
Fixes: dcfe378c81 ("lib: introduce support for page allocation tagging")
Signed-off-by: Hao Ge <hao.ge@linux.dev>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-18 00:10:50 -07:00
Kees Cook 69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Ran XiaokaiandAndrew Morton 77bcee8d40 alloc_tag: fix rw permission issue when handling boot parameter
Boot parameters prefixed with "sysctl." are processed during the final
stage of system initialization via kernel_init()-> do_sysctl_args().  When
CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled, the sysctl.vm.mem_profiling
entry is not writable and will cause a warning.

Before run_init_process(), system initialization executes in kernel thread
context.  Use current->mm to distinguish sysctl writes during
do_sysctl_args() from user-space triggered ones.

And when the proc_handler is from do_sysctl_args(), always return success
because the same value was already set by setup_early_mem_profiling() and
this eliminates a permission denied warning.

Link: https://lkml.kernel.org/r/20260115031536.164254-1-ranxiaokai627@163.com
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-31 14:22:37 -08:00
Joel GranadosandAndrew Morton 2a912d440c alloc_tag: move memory_allocation_profiling_sysctls into .rodata
Remove the change in file mode permissions done before initializing the
sysctl.  It is not necessary as the writing of the kernel variable will be
blocked by the proc_mem_profiling_handler when writing is disallowed (also
controlled by mem_profiling_support).

Link: https://lkml.kernel.org/r/20251215-jag-alloc_tag_const-v1-1-35ea56a1ce13@kernel.org
Signed-off-by: Joel Granados <joel.granados@kernel.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-20 19:24:31 -08:00
Zeng ChiandAndrew Morton 135e541ae8 lib/alloc_tag: use %pe format specifier
The %pe format specifier is designed to print error pointers.  It prints a
symbolic error name (eg.  -EINVAL) and it makes the code simpler by
omitting PTR_ERR();

This patch fixes this cocci report:
lib/alloc_tag.c:776:63-70: WARNING: Consider using %pe to print PTR_ERR()

Link: https://lkml.kernel.org/r/20251105023925.1447482-1-zeng_chi911@163.com
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-20 13:43:57 -08:00
Linus Torvalds e406d57be7 Merge tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:

 - "ida: Remove the ida_simple_xxx() API" from Christophe Jaillet
   completes the removal of this legacy IDR API

 - "panic: introduce panic status function family" from Jinchao Wang
   provides a number of cleanups to the panic code and its various
   helpers, which were rather ad-hoc and scattered all over the place

 - "tools/delaytop: implement real-time keyboard interaction support"
   from Fan Yu adds a few nice user-facing usability changes to the
   delaytop monitoring tool

 - "efi: Fix EFI boot with kexec handover (KHO)" from Evangelos
   Petrongonas fixes a panic which was happening with the combination of
   EFI and KHO

 - "Squashfs: performance improvement and a sanity check" from Phillip
   Lougher teaches squashfs's lseek() about SEEK_DATA/SEEK_HOLE. A mere
   150x speedup was measured for a well-chosen microbenchmark

 - plus another 50-odd singleton patches all over the place

* tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (75 commits)
  Squashfs: reject negative file sizes in squashfs_read_inode()
  kallsyms: use kmalloc_array() instead of kmalloc()
  MAINTAINERS: update Sibi Sankar's email address
  Squashfs: add SEEK_DATA/SEEK_HOLE support
  Squashfs: add additional inode sanity checking
  lib/genalloc: fix device leak in of_gen_pool_get()
  panic: remove CONFIG_PANIC_ON_OOPS_VALUE
  ocfs2: fix double free in user_cluster_connect()
  checkpatch: suppress strscpy warnings for userspace tools
  cramfs: fix incorrect physical page address calculation
  kernel: prevent prctl(PR_SET_PDEATHSIG) from racing with parent process exit
  Squashfs: fix uninit-value in squashfs_get_parent
  kho: only fill kimage if KHO is finalized
  ocfs2: avoid extra calls to strlen() after ocfs2_sprintf_system_inode_name()
  kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths
  sched/task.h: fix the wrong comment on task_lock() nesting with tasklist_lock
  coccinelle: platform_no_drv_owner: handle also built-in drivers
  coccinelle: of_table: handle SPI device ID tables
  lib/decompress: use designated initializers for struct compress_format
  efi: support booting with kexec handover (KHO)
  ...
2025-10-02 18:44:54 -07:00
Suren BaghdasaryanandAndrew Morton b9e2f58ffb alloc_tag: mark inaccurate allocation counters in /proc/allocinfo output
While rare, memory allocation profiling can contain inaccurate counters if
slab object extension vector allocation fails.  That allocation might
succeed later but prior to that, slab allocations that would have used
that object extension vector will not be accounted for.  To indicate
incorrect counters, "accurate:no" marker is appended to the call site line
in the /proc/allocinfo output.  Bump up /proc/allocinfo version to reflect
the change in the file format and update documentation.

Example output with invalid counters:
allocinfo - version: 2.0
           0        0 arch/x86/kernel/kdebugfs.c:105 func:create_setup_data_nodes
           0        0 arch/x86/kernel/alternative.c:2090 func:alternatives_smp_module_add
           0        0 arch/x86/kernel/alternative.c:127 func:__its_alloc accurate:no
           0        0 arch/x86/kernel/fpu/regset.c:160 func:xstateregs_set
           0        0 arch/x86/kernel/fpu/xstate.c:1590 func:fpstate_realloc
           0        0 arch/x86/kernel/cpu/aperfmperf.c:379 func:arch_enable_hybrid_capacity_scale
           0        0 arch/x86/kernel/cpu/amd_cache_disable.c:258 func:init_amd_l3_attrs
       49152       48 arch/x86/kernel/cpu/mce/core.c:2709 func:mce_device_create accurate:no
       32768        1 arch/x86/kernel/cpu/mce/genpool.c:132 func:mce_gen_pool_create
           0        0 arch/x86/kernel/cpu/mce/amd.c:1341 func:mce_threshold_create_device

[surenb@google.com: document new "accurate:no" marker]
  Fixes: 39d117e04d15 ("alloc_tag: mark inaccurate allocation counters in /proc/allocinfo output")
[akpm@linux-foundation.org: simplification per Usama, reflow text]
[akpm@linux-foundation.org: add newline to prevent docs warning, per Randy]
Link: https://lkml.kernel.org/r/20250915230224.4115531-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Cc: David Wang <00107082@163.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:36 -07:00
Suren BaghdasaryanandAndrew Morton 9e8a0bbb12 alloc_tag: prevent enabling memory profiling if it was shut down
Memory profiling can be shut down due to reasons like a failure during
initialization.  When this happens, the user should not be able to
re-enable it.  Current sysctrl interface does not handle this properly and
will allow re-enabling memory profiling.  Fix this by checking for this
condition during sysctrl write operation.

Link: https://lkml.kernel.org/r/20250915212756.3998938-3-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Cc: David Wang <00107082@163.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:30 -07:00
Suren BaghdasaryanandAndrew Morton 123bcf2842 alloc_tag: use release_pages() in the cleanup path
Patch series "Minor fixes for memory allocation profiling", v2.

Over the last couple months I gathered a few reports of minor issues in
memory allocation profiling which are addressed in this patchset.


This patch (of 2):

When bulk-freeing an array of pages use release_pages() instead of freeing
them page-by-page.

Link: https://lkml.kernel.org/r/20250915212756.3998938-1-surenb@google.com
Link: https://lkml.kernel.org/r/20250915212756.3998938-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Cc: David Wang <00107082@163.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:30 -07:00
Kuan-Wei ChiuandAndrew Morton 0ca863b7c6 alloc_tag: use str_on_off() helper
Replace the ternary (enable ?  "on" : "off") with the str_on_off() helper
from string_choices.h.  This improves readability by replacing the
three-operand ternary with a single function call, ensures consistent
string output, and allows potential string deduplication by the linker,
resulting in a slightly smaller binary.

Link: https://lkml.kernel.org/r/20250814093827.237980-1-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-13 17:32:47 -07:00
Andrew Morton cac3d177c0 Merge branch 'mm-hotfixes-stable' into mm-stable to pick up changes which
are required for a merge of the series "mm: folio_pte_batch()
improvements".
2025-07-12 14:48:26 -07:00
Hao GeandAndrew Morton 59b5ed409d mm/percpu: conditionally define _shared_alloc_tag via CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU
Recently discovered this entry while checking kallsyms on ARM64:
ffff800083e509c0 D _shared_alloc_tag

If ARCH_NEEDS_WEAK_PER_CPU is not defined(it is only defined for s390 and
alpha architectures), there's no need to statically define the percpu
variable _shared_alloc_tag.

Therefore, we need to implement isolation for this purpose.

When building the core kernel code for s390 or alpha architectures,
ARCH_NEEDS_WEAK_PER_CPU remains undefined (as it is gated by #if
defined(MODULE)).  However, when building modules for these architectures,
the macro is explicitly defined.

Therefore, we remove all instances of ARCH_NEEDS_WEAK_PER_CPU from the
code and introduced CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU to replace the
relevant logic.  We can now conditionally define the perpcu variable
_shared_alloc_tag based on CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU.  This
allows architectures (such as s390/alpha) that require weak definitions
for percpu variables in modules to include the definition, while others
can omit it via compile-time exclusion.

Link: https://lkml.kernel.org/r/20250618015809.1235761-1-hao.ge@linux.dev
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Suggested-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>	[s390]
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Chistoph Lameter <cl@linux.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-09 22:42:15 -07:00
David WangandAndrew Morton 9f44df50fe alloc_tag: keep codetag iterator active between read()
When reading /proc/allocinfo, for each read syscall, seq_file would invoke
start/stop callbacks.  In start callback, a memory is alloced to store
iterator and the iterator would start from beginning to walk linearly to
current read position.

seq_file read() takes at most 4096 bytes, even if read with a larger user
space buffer, meaning read out all of /proc/allocinfo, tens of read
syscalls are needed.  For example, a 306036 bytes allocinfo files need 76
reads:

 $ sudo cat /proc/allocinfo  | wc
    3964   16678  306036
 $ sudo strace -T -e read cat /proc/allocinfo
 ...
 read(3, "        4096        1 arch/x86/k"..., 131072) = 4063 <0.000062>
 ...
 read(3, "           0        0 sound/core"..., 131072) = 4021 <0.000150>
 ...
For those n=3964 lines, each read takes about m=3964/76=52 lines,
since iterator restart from beginning for each read(),
it would move forward
   m  steps on 1st read
 2*m  steps on 2nd read
 3*m  steps on 3rd read
 ...
   n  steps on last read
As read() along, those linear seek steps make read() calls slower and
slower.  Adding those up, codetag iterator moves about O(n*n/m) steps,
making data structure traversal take significant part of the whole
reading.  Profiling when stress reading /proc/allocinfo confirms it:

 vfs_read(99.959% 1677299/1677995)
     proc_reg_read_iter(99.856% 1674881/1677299)
         seq_read_iter(99.959% 1674191/1674881)
             allocinfo_start(75.664% 1266755/1674191)
                 codetag_next_ct(79.217% 1003487/1266755)  <---
                 srso_return_thunk(1.264% 16011/1266755)
                 __kmalloc_cache_noprof(0.102% 1296/1266755)
                 ...
             allocinfo_show(21.287% 356378/1674191)
             allocinfo_next(1.530% 25621/1674191)
codetag_next_ct() takes major part.

A private data alloced at open() time can be used to carry iterator alive
across read() calls, and avoid the memory allocation and iterator reset
for each read().  This way, only O(1) memory allocation and O(n) steps
iterating, and `time` shows performance improvement from ~7ms to ~4ms. 
Profiling with the change:

 vfs_read(99.865% 1581073/1583214)
     proc_reg_read_iter(99.485% 1572934/1581073)
         seq_read_iter(99.846% 1570519/1572934)
             allocinfo_show(87.428% 1373074/1570519)
                 seq_buf_printf(83.695% 1149196/1373074)
                 seq_buf_putc(1.917% 26321/1373074)
                 _find_next_bit(1.531% 21023/1373074)
                 ...
                 codetag_to_text(0.490% 6727/1373074)
                 ...
             allocinfo_next(6.275% 98543/1570519)
             ...
             allocinfo_start(0.369% 5790/1570519)
             ...
Now seq_buf_printf() takes major part.

Link: https://lkml.kernel.org/r/20250609064408.112783-1-00107082@163.com
Signed-off-by: David Wang <00107082@163.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-09 22:42:06 -07:00
Harry YooandAndrew Morton 99af22cd34 lib/alloc_tag: do not acquire non-existent lock in alloc_tag_top_users()
alloc_tag_top_users() attempts to lock alloc_tag_cttype->mod_lock even
when the alloc_tag_cttype is not allocated because:

  1) alloc tagging is disabled because mem profiling is disabled
     (!alloc_tag_cttype)
  2) alloc tagging is enabled, but not yet initialized (!alloc_tag_cttype)
  3) alloc tagging is enabled, but failed initialization
     (!alloc_tag_cttype or IS_ERR(alloc_tag_cttype))

In all cases, alloc_tag_cttype is not allocated, and therefore
alloc_tag_top_users() should not attempt to acquire the semaphore.

This leads to a crash on memory allocation failure by attempting to
acquire a non-existent semaphore:

  Oops: general protection fault, probably for non-canonical address 0xdffffc000000001b: 0000 [#3] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x00000000000000d8-0x00000000000000df]
  CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G      D             6.16.0-rc2 #1 VOLUNTARY
  Tainted: [D]=DIE
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
  RIP: 0010:down_read_trylock+0xaa/0x3b0
  Code: d0 7c 08 84 d2 0f 85 a0 02 00 00 8b 0d df 31 dd 04 85 c9 75 29 48 b8 00 00 00 00 00 fc ff df 48 8d 6b 68 48 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 88 02 00 00 48 3b 5b 68 0f 85 53 01 00 00 65 ff
  RSP: 0000:ffff8881002ce9b8 EFLAGS: 00010016
  RAX: dffffc0000000000 RBX: 0000000000000070 RCX: 0000000000000000
  RDX: 000000000000001b RSI: 000000000000000a RDI: 0000000000000070
  RBP: 00000000000000d8 R08: 0000000000000001 R09: ffffed107dde49d1
  R10: ffff8883eef24e8b R11: ffff8881002cec20 R12: 1ffff11020059d37
  R13: 00000000003fff7b R14: ffff8881002cec20 R15: dffffc0000000000
  FS:  00007f963f21d940(0000) GS:ffff888458ca6000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f963f5edf71 CR3: 000000010672c000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   codetag_trylock_module_list+0xd/0x20
   alloc_tag_top_users+0x369/0x4b0
   __show_mem+0x1cd/0x6e0
   warn_alloc+0x2b1/0x390
   __alloc_frozen_pages_noprof+0x12b9/0x21a0
   alloc_pages_mpol+0x135/0x3e0
   alloc_slab_page+0x82/0xe0
   new_slab+0x212/0x240
   ___slab_alloc+0x82a/0xe00
   </TASK>

As David Wang points out, this issue became easier to trigger after commit
780138b123 ("alloc_tag: check mem_profiling_support in alloc_tag_init").

Before the commit, the issue occurred only when it failed to allocate and
initialize alloc_tag_cttype or if a memory allocation fails before
alloc_tag_init() is called.  After the commit, it can be easily triggered
when memory profiling is compiled but disabled at boot.

To properly determine whether alloc_tag_init() has been called and its
data structures initialized, verify that alloc_tag_cttype is a valid
pointer before acquiring the semaphore.  If the variable is NULL or an
error value, it has not been properly initialized.  In such a case, just
skip and do not attempt to acquire the semaphore.

[harry.yoo@oracle.com: v3]
  Link: https://lkml.kernel.org/r/20250624072513.84219-1-harry.yoo@oracle.com
Link: https://lkml.kernel.org/r/20250620195305.1115151-1-harry.yoo@oracle.com
Fixes: 780138b123 ("alloc_tag: check mem_profiling_support in alloc_tag_init")
Fixes: 1438d349d1 ("lib: add memory allocations report in show_mem()")
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202506181351.bba867dd-lkp@intel.com
Acked-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: Raghavendra K T <raghavendra.kt@amd.com>
Cc: Casey Chen <cachen@purestorage.com>
Cc: David Wang <00107082@163.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Yuanyuan Zhong <yzhong@purestorage.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-09 21:07:52 -07:00
Hao GeandAndrew Morton f5769359c5 mm/alloc_tag: fix the kmemleak false positive issue in the allocation of the percpu variable tag->counters
When loading a module, as long as the module has memory allocation
operations, kmemleak produces a false positive report that resembles the
following:

unreferenced object (percpu) 0x7dfd232a1650 (size 16):
  comm "modprobe", pid 1301, jiffies 4294940249
  hex dump (first 16 bytes on cpu 2):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 0):
    kmemleak_alloc_percpu+0xb4/0xd0
    pcpu_alloc_noprof+0x700/0x1098
    load_module+0xd4/0x348
    codetag_module_init+0x20c/0x450
    codetag_load_module+0x70/0xb8
    load_module+0xef8/0x1608
    init_module_from_file+0xec/0x158
    idempotent_init_module+0x354/0x608
    __arm64_sys_finit_module+0xbc/0x150
    invoke_syscall+0xd4/0x258
    el0_svc_common.constprop.0+0xb4/0x240
    do_el0_svc+0x48/0x68
    el0_svc+0x40/0xf8
    el0t_64_sync_handler+0x10c/0x138
    el0t_64_sync+0x1ac/0x1b0

This is because the module can only indirectly reference
alloc_tag_counters through the alloc_tag section, which misleads kmemleak.

However, we don't have a kmemleak ignore interface for percpu allocations
yet.  So let's create one and invoke it for tag->counters.

[gehao@kylinos.cn: fix build error when CONFIG_DEBUG_KMEMLEAK=n, s/igonore/ignore/]
  Link: https://lkml.kernel.org/r/20250620093102.2416767-1-hao.ge@linux.dev
Link: https://lkml.kernel.org/r/20250619183154.2122608-1-hao.ge@linux.dev
Fixes: 12ca42c237 ("alloc_tag: allocate percpu counters for module tags dynamically")
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>	[lib/alloc_tag.c]
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-06-25 15:55:03 -07:00
Suren BaghdasaryanandAndrew Morton 044d2aee6c alloc_tag: handle module codetag load errors as module load failures
Failures inside codetag_load_module() are currently ignored.  As a result
an error there would not cause a module load failure and freeing of the
associated resources.  Correct this behavior by propagating the error code
to the caller and handling possible errors.  With this change, error to
allocate percpu counters, which happens at this stage, will not be ignored
and will cause a module load failure and freeing of resources.  With this
change we also do not need to disable memory allocation profiling when
this error happens, instead we fail to load the module.

Link: https://lkml.kernel.org/r/20250521160602.1940771-1-surenb@google.com
Fixes: 10075262888b ("alloc_tag: allocate percpu counters for module tags dynamically")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: Casey Chen <cachen@purestorage.com>
Closes: https://lore.kernel.org/all/20250520231620.15259-1-cachen@purestorage.com/
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Wang <00107082@163.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-06-05 22:02:23 -07:00
Linus Torvalds 00c010e130 Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp->free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...
2025-05-31 15:44:16 -07:00
Suren BaghdasaryanandAndrew Morton 12ca42c237 alloc_tag: allocate percpu counters for module tags dynamically
When a module gets unloaded it checks whether any of its tags are still in
use and if so, we keep the memory containing module's allocation tags
alive until all tags are unused.  However percpu counters referenced by
the tags are freed by free_module().  This will lead to UAF if the memory
allocated by a module is accessed after module was unloaded.

To fix this we allocate percpu counters for module allocation tags
dynamically and we keep it alive for tags which are still in use after
module unloading.  This also removes the requirement of a larger
PERCPU_MODULE_RESERVE when memory allocation profiling is enabled because
percpu memory for counters does not need to be reserved anymore.

Link: https://lkml.kernel.org/r/20250517000739.5930-1-surenb@google.com
Fixes: 0db6f8d782 ("alloc_tag: load module tags into separate contiguous memory")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: David Wang <00107082@163.com>
Closes: https://lore.kernel.org/all/20250516131246.6244-1-00107082@163.com/
Tested-by: David Wang <00107082@163.com>
Cc: Christoph Lameter (Ampere) <cl@gentwo.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-25 00:53:48 -07:00
Casey ChenandAndrew Morton 780138b123 alloc_tag: check mem_profiling_support in alloc_tag_init
If mem_profiling_support is false, for example by
sysctl.vm.mem_profiling=never, alloc_tag_init should skip module tags
allocation, codetag type registration and procfs init.

Link: https://lkml.kernel.org/r/20250513182602.121843-1-cachen@purestorage.com
Signed-off-by: Casey Chen <cachen@purestorage.com>
Reviewed-by: Yuanyuan Zhong <yzhong@purestorage.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-22 14:55:38 -07:00
T.J. MercierandAndrew Morton e6e07b696d alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate
alloc_pages_bulk_node() may partially succeed and allocate fewer than the
requested nr_pages.  There are several conditions under which this can
occur, but we have encountered the case where CONFIG_PAGE_OWNER is enabled
causing all bulk allocations to always fallback to single page allocations
due to commit 187ad460b8 ("mm/page_alloc: avoid page allocator recursion
with pagesets.lock held").

Currently vm_module_tags_populate() immediately fails when
alloc_pages_bulk_node() returns fewer than the requested number of pages. 
When this happens memory allocation profiling gets disabled, for example

[   14.297583] [9:       modprobe:  465] Failed to allocate memory for allocation tags in the module scsc_wlan. Memory allocation profiling is disabled!
[   14.299339] [9:       modprobe:  465] modprobe: Failed to insmod '/vendor/lib/modules/scsc_wlan.ko' with args '': Out of memory

This patch causes vm_module_tags_populate() to retry bulk allocations for
the remaining memory instead of failing immediately which will avoid the
disablement of memory allocation profiling.

Link: https://lkml.kernel.org/r/20250409225111.3770347-1-tjmercier@google.com
Fixes: 0f9b685626 ("alloc_tag: populate memory for module tags as needed")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Reported-by: Janghyuck Kim <janghyuck.kim@samsung.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-04-11 17:32:41 -07:00
Suren BaghdasaryanandAndrew Morton 51ff4d7486 mm: avoid extra mem_alloc_profiling_enabled() checks
Refactor code to avoid extra mem_alloc_profiling_enabled() checks inside
pgalloc_tag_get() function which is often called after that check was
already done.

Link: https://lkml.kernel.org/r/20250201231803.2661189-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: David Wang <00107082@163.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Minchan Kim <minchan@google.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16 22:06:03 -07:00