linux-stable.git/include/linux, branch v6.6.140

mm/damon/lru_sort: detect and use fresh enabled and kdamond_pid values

2026-05-17T15:13:53+00:00

commit b98b7ff6025ae82570d4915e083f0cbd8d48b3cf upstream.

DAMON_LRU_SORT updates 'enabled' and 'kdamond_pid' parameter values, which
represents the running status of its kdamond, when the user explicitly
requests start/stop of the kdamond.  The kdamond can, however, be stopped
in events other than the explicit user request in the following three
events.

1. ctx->regions_score_histogram allocation failure at beginning of the
   execution,
2. damon_commit_ctx() failure due to invalid user input, and
3. damon_commit_ctx() failure due to its internal allocation failures.

Hence, if the kdamond is stopped by the above three events, the values of
the status parameters can be stale.  Users could show the stale values and
be confused.  This is already bad, but the real consequence is worse.
DAMON_LRU_SORT avoids unnecessary damon_start() and damon_stop() calls
based on the 'enabled' parameter value.  And the update of 'enabled'
parameter value depends on the damon_start() and damon_stop() call
results.  Hence, once the kdamond has stopped by the unintentional events,
the user cannot restart the kdamond before the system reboot.  For
example, the issue can be reproduced via below steps.

    # cd /sys/module/damon_lru_sort/parameters
    #
    # # start DAMON_LRU_SORT
    # echo Y > enabled
    # ps -ef | grep kdamond
    root         806       2  0 17:53 ?        00:00:00 [kdamond.0]
    root         808     803  0 17:53 pts/4    00:00:00 grep kdamond
    #
    # # commit wrong input to stop kdamond withou explicit stop request
    # echo 3 > addr_unit
    # echo Y > commit_inputs
    bash: echo: write error: Invalid argument
    #
    # # confirm kdamond is stopped
    # ps -ef | grep kdamond
    root         811     803  0 17:53 pts/4    00:00:00 grep kdamond
    #
    # # users casn now show stable status
    # cat enabled
    Y
    # cat kdamond_pid
    806
    #
    # # even after fixing the wrong parameter,
    # # kdamond cannot be restarted.
    # echo 1 > addr_unit
    # echo Y > enabled
    # ps -ef | grep kdamond
    root         815     803  0 17:54 pts/4    00:00:00 grep kdamond

The problem will only rarely happen in real and common setups for the
following reasons.  The allocation failures are unlikely in such setups
since those allocations are arguably too small to fail.  Also sane users
on real production environments may not commit wrong input parameters.
But once it happens, the consequence is quite bad.  And the bug is a bug.

The issue stems from the fact that there are multiple events that can
change the status, and following all the events is challenging.
Dynamically detect and use the fresh status for the parameters when those
are requested.

Link: https://lore.kernel.org/20260419161003.79176-3-sj@kernel.org
Fixes: 40e983cca927 ("mm/damon: introduce DAMON-based LRU-lists Sorting")
Co-developed-by: Liew Rui Yan 
Signed-off-by: Liew Rui Yan 
Signed-off-by: SeongJae Park 
Cc:  # 6.0.x
Signed-off-by: Andrew Morton 
Signed-off-by: SeongJae Park 
(port parts of 42b7491af14c ("mm/damon/core: introduce damon_call()")
and d2b5be741a50 ("mm/damon/sysfs: use DAMON core API
damon_is_running()") for damon_is_running() dependency)
Signed-off-by: Greg Kroah-Hartman

mm/damon/core: implement damon_kdamond_pid()

2026-05-17T15:13:53+00:00

commit 4262c53236977de3ceaa3bf2aefdf772c9b874dd upstream.

Patch series "mm/damon: hide kdamond and kdamond_lock from API callers".

'kdamond' and 'kdamond_lock' fields initially exposed to DAMON API callers
for flexible synchronization and use cases.  As DAMON API became somewhat
complicated compared to the early days, Keeping those exposed could only
encourage the API callers to invent more creative but complicated and
difficult-to-debug use cases.

Fortunately DAMON API callers didn't invent that many creative use cases.
There exist only two use cases of 'kdamond' and 'kdamond_lock'.  Finding
whether the kdamond is actively running, and getting the pid of the
kdamond.  For the first use case, a dedicated API function, namely
'damon_is_running()' is provided, and all DAMON API callers are using the
function for the use case.  Hence only the second use case is where the
fields are directly being used by DAMON API callers.

To prevent future invention of complicated and erroneous use cases of the
fields, hide the fields from the API callers.  For that, provide new
dedicated DAMON API functions for the remaining use case, namely
damon_kdamond_pid(), migrate DAMON API callers to use the new function,
and mark the fields as private fields.


This patch (of 5):

'kdamond' and 'kdamond_lock' are directly being used by DAMON API callers
for getting the pid of the corresponding kdamond.  To discourage invention
of creative but complicated and erroneous new usages of the fields that
require careful synchronization, implement a new API function that can
simply be used without the manual synchronizations.

Link: https://lkml.kernel.org/r/20260115152047.68415-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260115152047.68415-2-sj@kernel.org
Signed-off-by: SeongJae Park 
Signed-off-by: Andrew Morton 
Signed-off-by: SeongJae Park 
Signed-off-by: Greg Kroah-Hartman

printk: add print_hex_dump_devel()

2026-05-17T15:13:50+00:00

[ Upstream commit d134feeb5df33fbf77f482f52a366a44642dba09 ]

Add print_hex_dump_devel() as the hex dump equivalent of pr_devel(),
which emits output only when DEBUG is enabled, but keeps call sites
compiled otherwise.

Suggested-by: Herbert Xu 
Signed-off-by: Thorsten Blum 
Reviewed-by: John Ogness 
Signed-off-by: Herbert Xu 
Stable-dep-of: 177730a273b1 ("crypto: caam - guard HMAC key hex dumps in hash_digest_key")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mmc: core: Optimize time for secure erase/trim for some Kingston eMMCs

2026-05-17T15:13:49+00:00

[ Upstream commit d6bf2e64dec87322f2b11565ddb59c0e967f96e3 ]

Kingston eMMC IY2964 and IB2932 takes a fixed ~2 seconds for each secure
erase/trim operation regardless of size - that is, a single secure
erase/trim operation of 1MB takes the same time as 1GB. With default
calculated 3.5MB max discard size, secure erase 1GB requires ~300 separate
operations taking ~10 minutes total.

Add a card quirk, MMC_QUIRK_FIXED_SECURE_ERASE_TRIM_TIME, to set maximum
secure erase size for those devices. This allows 1GB secure erase to
complete in a single operation, reducing time from 10 minutes to just 2
seconds.

Signed-off-by: Luke Wang 
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson 
[ adapted `lim->max_secure_erase_sectors =` assignment to `blk_queue_max_secure_erase_sectors(q, ...)` setter and used pre-rename `mmc_can_secure_erase_trim`/`mmc_can_trim` helpers ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

fbdev: defio: Disconnect deferred I/O from the lifetime of struct fb_info

2026-05-17T15:13:49+00:00

[ Upstream commit 9ded47ad003f09a94b6a710b5c47f4aa5ceb7429 ]

Hold state of deferred I/O in struct fb_deferred_io_state. Allocate an
instance as part of initializing deferred I/O and remove it only after
the final mapping has been closed. If the fb_info and the contained
deferred I/O meanwhile goes away, clear struct fb_deferred_io_state.info
to invalidate the mapping. Any access will then result in a SIGBUS
signal.

Fixes a long-standing problem, where a device hot-unplug happens while
user space still has an active mapping of the graphics memory. The hot-
unplug frees the instance of struct fb_info. Accessing the memory will
operate on undefined state.

Signed-off-by: Thomas Zimmermann 
Fixes: 60b59beafba8 ("fbdev: mm: Deferred IO support")
Cc: Helge Deller 
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # v2.6.22+
Signed-off-by: Helge Deller 
[ replaced `kzalloc_obj` with `kzalloc`, and dropped `mutex_destroy(&fbdefio->lock)` ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

fanotify: fix false positive on permission events

2026-05-17T15:13:38+00:00

commit 7746e3bd4cc19b5092e00d32d676e329bfcb6900 upstream.

fsnotify_get_mark_safe() may return false for a mark on an unrelated group,
which results in bypassing the permission check.

Fix by skipping over detached marks that are not in the current group.

CC: stable@vger.kernel.org
Fixes: abc77577a669 ("fsnotify: Provide framework for dropping SRCU lock in ->handle_event")
Signed-off-by: Miklos Szeredi 
Link: https://patch.msgid.link/20260410144950.156160-1-mszeredi@redhat.com
Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

bpf: support non-r10 register spill/fill to/from stack in precision tracking

2026-05-17T15:13:36+00:00

[ Upstream commit 41f6f64e6999a837048b1bd13a2f8742964eca6b ]

Use instruction (jump) history to record instructions that performed
register spill/fill to/from stack, regardless if this was done through
read-only r10 register, or any other register after copying r10 into it
*and* potentially adjusting offset.

To make this work reliably, we push extra per-instruction flags into
instruction history, encoding stack slot index (spi) and stack frame
number in extra 10 bit flags we take away from prev_idx in instruction
history. We don't touch idx field for maximum performance, as it's
checked most frequently during backtracking.

This change removes basically the last remaining practical limitation of
precision backtracking logic in BPF verifier. It fixes known
deficiencies, but also opens up new opportunities to reduce number of
verified states, explored in the subsequent patches.

There are only three differences in selftests' BPF object files
according to veristat, all in the positive direction (less states).

File                                    Program        Insns (A)  Insns (B)  Insns  (DIFF)  States (A)  States (B)  States (DIFF)
--------------------------------------  -------------  ---------  ---------  -------------  ----------  ----------  -------------
test_cls_redirect_dynptr.bpf.linked3.o  cls_redirect        2987       2864  -123 (-4.12%)         240         231    -9 (-3.75%)
xdp_synproxy_kern.bpf.linked3.o         syncookie_tc       82848      82661  -187 (-0.23%)        5107        5073   -34 (-0.67%)
xdp_synproxy_kern.bpf.linked3.o         syncookie_xdp      85116      84964  -152 (-0.18%)        5162        5130   -32 (-0.62%)

Note, I avoided renaming jmp_history to more generic insn_hist to
minimize number of lines changed and potential merge conflicts between
bpf and bpf-next trees.

Notice also cur_hist_entry pointer reset to NULL at the beginning of
instruction verification loop. This pointer avoids the problem of
relying on last jump history entry's insn_idx to determine whether we
already have entry for current instruction or not. It can happen that we
added jump history entry because current instruction is_jmp_point(), but
also we need to add instruction flags for stack access. In this case, we
don't want to entries, so we need to reuse last added entry, if it is
present.

Relying on insn_idx comparison has the same ambiguity problem as the one
that was fixed recently in [0], so we avoid that.

  [0] https://patchwork.kernel.org/project/netdevbpf/patch/20231110002638.4168352-3-andrii@kernel.org/

Acked-by: Eduard Zingerman 
Reported-by: Tao Lyu 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20231205184248.1502704-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov 
[ Note: Adapted the expected log format for selftests as the map format
  in verifier logs was changed in commits 1db747d75b1d and
  0c95c9fdb696. ]
Signed-off-by: Paul Chaignon 
Acked-by: Shung-Hsi Yu 
Acked-by: Daniel Borkmann 
Signed-off-by: Sasha Levin

x86: shadow stacks: proper error handling for mmap lock

2026-05-17T15:13:34+00:00

[ Upstream commit 52f657e34d7b21b47434d9d8b26fa7f6778b63a0 ]

김영민 reports that shstk_pop_sigframe() doesn't check for errors from
mmap_read_lock_killable(), which is a silly oversight, and also shows
that we haven't marked those functions with "__must_check", which would
have immediately caught it.

So let's fix both issues.

Reported-by: 김영민 
Acked-by: Oleg Nesterov 
Acked-by: Dave Hansen 
Acked-by: Rick Edgecombe 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

driver core: Add kernel-doc for DEV_FLAG_COUNT enum value

2026-05-17T15:13:33+00:00

commit 5b484311507b5d403c1f7a45f6aa3778549e268b upstream.

Even though nobody should use this value (except when declaring the
"flags" bitmap), kernel-doc still gets upset that it's not documented.
It reports:

  WARNING: ../include/linux/device.h:519
  Enum value 'DEV_FLAG_COUNT' not described in enum 'struct_device_flags'

Add the description of DEV_FLAG_COUNT.

Fixes: a2225b6e834a ("driver core: Don't let a device probe until it's ready")
Reported-by: Randy Dunlap 
Closes: https://lore.kernel.org/f318cd43-81fd-48b9-abf7-92af85f12f91@infradead.org
Signed-off-by: Douglas Anderson 
Tested-by: Randy Dunlap 
Reviewed-by: Randy Dunlap 
Link: https://patch.msgid.link/20260413195910.1.I23aca74fe2d3636a47df196a80920fecb2643220@changeid
Signed-off-by: Danilo Krummrich 
Signed-off-by: Greg Kroah-Hartman

randomize_kstack: Maintain kstack_offset per task

2026-05-17T15:13:30+00:00

commit 37beb42560165869838e7d91724f3e629db64129 upstream.

kstack_offset was previously maintained per-cpu, but this caused a
couple of issues. So let's instead make it per-task.

Issue 1: add_random_kstack_offset() and choose_random_kstack_offset()
expected and required to be called with interrupts and preemption
disabled so that it could manipulate per-cpu state. But arm64, loongarch
and risc-v are calling them with interrupts and preemption enabled. I
don't _think_ this causes any functional issues, but it's certainly
unexpected and could lead to manipulating the wrong cpu's state, which
could cause a minor performance degradation due to bouncing the cache
lines. By maintaining the state per-task those functions can safely be
called in preemptible context.

Issue 2: add_random_kstack_offset() is called before executing the
syscall and expands the stack using a previously chosen random offset.
choose_random_kstack_offset() is called after executing the syscall and
chooses and stores a new random offset for the next syscall. With
per-cpu storage for this offset, an attacker could force cpu migration
during the execution of the syscall and prevent the offset from being
updated for the original cpu such that it is predictable for the next
syscall on that cpu. By maintaining the state per-task, this problem
goes away because the per-task random offset is updated after the
syscall regardless of which cpu it is executing on.

Fixes: 39218ff4c625 ("stack: Optionally randomize kernel stack offset each syscall")
Closes: https://lore.kernel.org/all/dd8c37bc-795f-4c7a-9086-69e584d8ab24@arm.com/
Cc: stable@vger.kernel.org
Acked-by: Mark Rutland 
Signed-off-by: Ryan Roberts 
Link: https://patch.msgid.link/20260303150840.3789438-2-ryan.roberts@arm.com
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman