linux-stable.git/kernel, branch v6.18.27 Linux kernel stable tree rtmutex: Use waiter::task instead of current in remove_waiter() 2026-05-07T04:11:59+00:00 Keenan Dong keenanat2000@gmail.com 2026-04-08T08:46:00+00:00 3fb7394a837740770f0d6b4b30567e60786a63f2 commit 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 upstream. remove_waiter() is used by the slowlock paths, but it is also used for proxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from futex_requeue(). In the latter case waiter::task is not current, but remove_waiter() operates on current for the dequeue operation. That results in several problems: 1) the rbtree dequeue happens without waiter::task::pi_lock being held 2) the waiter task's pi_blocked_on state is not cleared, which leaves a dangling pointer primed for UAF around. 3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter task Use waiter::task instead of current in all related operations in remove_waiter() to cure those problems. [ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the changelog ] Fixes: 8161239a8bcc ("rtmutex: Simplify PI algorithm and make highest prio task get lock") Reported-by: Yuan Tan <yuantan098@gmail.com> Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Reported-by: Xin Liu <bird@lzu.edu.cn> Signed-off-by: Keenan Dong <keenanat2000@gmail.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 upstream.

remove_waiter() is used by the slowlock paths, but it is also used for
proxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from
futex_requeue().

In the latter case waiter::task is not current, but remove_waiter()
operates on current for the dequeue operation. That results in several
problems:

  1) the rbtree dequeue happens without waiter::task::pi_lock being held

  2) the waiter task's pi_blocked_on state is not cleared, which leaves a
     dangling pointer primed for UAF around.

  3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter
     task

Use waiter::task instead of current in all related operations in
remove_waiter() to cure those problems.

[ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the
  	changelog ]

Fixes: 8161239a8bcc ("rtmutex: Simplify PI algorithm and make highest prio task get lock")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Keenan Dong <keenanat2000@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
taskstats: set version in TGID exit notifications 2026-05-07T04:11:56+00:00 Yiyang Chen cyyzero16@gmail.com 2026-03-29T19:00:40+00:00 e88827bb039904d323aa619d771ae4e54c5b1e2a commit 16c4f0211aaa1ec1422b11b59f64f1abe9009fc0 upstream. delay accounting started populating taskstats records with a valid version field via fill_pid() and fill_tgid(). Later, commit ad4ecbcba728 ("[PATCH] delay accounting taskstats interface send tgid once") changed the TGID exit path to send the cached signal->stats aggregate directly instead of building the outgoing record through fill_tgid(). Unlike fill_tgid(), fill_tgid_exit() only accumulates accounting data and never initializes stats->version. As a result, TGID exit notifications can reach userspace with version == 0 even though PID exit notifications and TASKSTATS_CMD_GET replies carry a valid taskstats version. This is easy to reproduce with `tools/accounting/getdelays.c`. I have a small follow-up patch for that tool which: 1. increases the receive buffer/message size so the pid+tgid combined exit notification is not dropped/truncated 2. prints `stats->version`. With that patch, the reproducer is: Terminal 1: ./getdelays -d -v -l -m 0 Terminal 2: taskset -c 0 python3 -c 'import threading,time; t=threading.Thread(target=time.sleep,args=(0.1,)); t.start(); t.join()' That produces both PID and TGID exit notifications for the same process. The PID exit record reports a valid taskstats version, while the TGID exit record reports `version 0`. This patch (of 2): Set stats->version = TASKSTATS_VERSION after copying the cached TGID aggregate into the outgoing netlink payload so all taskstats records are self-describing again. Link: https://lkml.kernel.org/r/ba83d934e59edd431b693607de573eb9ca059309.1774810498.git.cyyzero16@gmail.com Fixes: ad4ecbcba728 ("[PATCH] delay accounting taskstats interface send tgid once") Signed-off-by: Yiyang Chen <cyyzero16@gmail.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Dr. Thomas Orgis <thomas.orgis@uni-hamburg.de> Cc: Fan Yu <fan.yu9@zte.com.cn> Cc: Wang Yaxin <wang.yaxin@zte.com.cn> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 16c4f0211aaa1ec1422b11b59f64f1abe9009fc0 upstream.

delay accounting started populating taskstats records with a valid version
field via fill_pid() and fill_tgid().

Later, commit ad4ecbcba728 ("[PATCH] delay accounting taskstats interface
send tgid once") changed the TGID exit path to send the cached
signal->stats aggregate directly instead of building the outgoing record
through fill_tgid().  Unlike fill_tgid(), fill_tgid_exit() only
accumulates accounting data and never initializes stats->version.

As a result, TGID exit notifications can reach userspace with version == 0
even though PID exit notifications and TASKSTATS_CMD_GET replies carry a
valid taskstats version.

This is easy to reproduce with `tools/accounting/getdelays.c`.

I have a small follow-up patch for that tool which:

1. increases the receive buffer/message size so the pid+tgid
   combined exit notification is not dropped/truncated

2. prints `stats->version`.

With that patch, the reproducer is:

  Terminal 1:
    ./getdelays -d -v -l -m 0

  Terminal 2:
    taskset -c 0 python3 -c 'import threading,time; t=threading.Thread(target=time.sleep,args=(0.1,)); t.start(); t.join()'

That produces both PID and TGID exit notifications for the same
process.  The PID exit record reports a valid taskstats version, while
the TGID exit record reports `version 0`.


This patch (of 2):

Set stats->version = TASKSTATS_VERSION after copying the cached TGID
aggregate into the outgoing netlink payload so all taskstats records are
self-describing again.

Link: https://lkml.kernel.org/r/ba83d934e59edd431b693607de573eb9ca059309.1774810498.git.cyyzero16@gmail.com
Fixes: ad4ecbcba728 ("[PATCH] delay accounting taskstats interface send tgid once")
Signed-off-by: Yiyang Chen <cyyzero16@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dr. Thomas Orgis <thomas.orgis@uni-hamburg.de>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ring-buffer: Do not double count the reader_page 2026-05-07T04:11:54+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-04-24T06:52:10+00:00 6b4bf6519e5071492f7bcd3e237dceb57457b8b6 commit 92d5a606721f759ebebf448b3bd2b7a781d50bd0 upstream. Since the cpu_buffer->reader_page is updated if there are unwound pages. After that update, we should skip the page if it is the original reader_page, because the original reader_page is already checked. Cc: stable@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Ian Rogers <irogers@google.com> Link: https://patch.msgid.link/177701353063.2223789.1471163147644103306.stgit@mhiramat.tok.corp.google.com Fixes: ca296d32ece3 ("tracing: ring_buffer: Rewind persistent ring buffer on reboot") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 92d5a606721f759ebebf448b3bd2b7a781d50bd0 upstream.

Since the cpu_buffer->reader_page is updated if there are unwound
pages. After that update, we should skip the page if it is the
original reader_page, because the original reader_page is already
checked.

Cc: stable@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/177701353063.2223789.1471163147644103306.stgit@mhiramat.tok.corp.google.com
Fixes: ca296d32ece3 ("tracing: ring_buffer: Rewind persistent ring buffer on reboot")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
randomize_kstack: Maintain kstack_offset per task 2026-05-07T04:11:47+00:00 Ryan Roberts ryan.roberts@arm.com 2026-03-03T15:08:38+00:00 d780f24a4939862e1df9def415fe7de59280fc7c 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 <mark.rutland@arm.com> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Link: https://patch.msgid.link/20260303150840.3789438-2-ryan.roberts@arm.com Signed-off-by: Kees Cook <kees@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-2-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/fprobe: Reject registration of a registered fprobe before init 2026-05-07T04:11:46+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-04-20T14:00:48+00:00 f344f04e33bfeb8655996f0c6c71e460e86d4319 commit 6ad51ada17ed80c9a5f205b4c01c424cac8b0d46 upstream. Reject registration of a registered fprobe which is on the fprobe hash table before initializing fprobe. The add_fprobe_hash() checks this re-register fprobe, but since fprobe_init() clears hlist_array field, it is too late to check it. It has to check the re-registration before touncing fprobe. Link: https://lore.kernel.org/all/177669364845.132053.18375367916162315835.stgit@mhiramat.tok.corp.google.com/ Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6ad51ada17ed80c9a5f205b4c01c424cac8b0d46 upstream.

Reject registration of a registered fprobe which is on the fprobe
hash table before initializing fprobe.
The add_fprobe_hash() checks this re-register fprobe, but since
fprobe_init() clears hlist_array field, it is too late to check it.
It has to check the re-registration before touncing fprobe.

Link: https://lore.kernel.org/all/177669364845.132053.18375367916162315835.stgit@mhiramat.tok.corp.google.com/

Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched: Use u64 for bandwidth ratio calculations 2026-05-07T04:11:40+00:00 Joseph Salisbury joseph.salisbury@oracle.com 2026-04-03T21:00:14+00:00 558aa1e2cd11741ebc5dd57fd17cb3fd98c5fd64 commit c6e80201e057dfb7253385e60bf541121bf5dc33 upstream. to_ratio() computes BW_SHIFT-scaled bandwidth ratios from u64 period and runtime values, but it returns unsigned long. tg_rt_schedulable() also stores the current group limit and the accumulated child sum in unsigned long. On 32-bit builds, large bandwidth ratios can be truncated and the RT group sum can wrap when enough siblings are present. That can let an overcommitted RT hierarchy pass the schedulability check, and it also narrows the helper result for other callers. Return u64 from to_ratio() and use u64 for the RT group totals so bandwidth ratios are preserved and compared at full width on both 32-bit and 64-bit builds. Fixes: b40b2e8eb521 ("sched: rt: multi level group constraints") Assisted-by: Codex:GPT-5 Signed-off-by: Joseph Salisbury <joseph.salisbury@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260403210014.2713404-1-joseph.salisbury@oracle.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c6e80201e057dfb7253385e60bf541121bf5dc33 upstream.

to_ratio() computes BW_SHIFT-scaled bandwidth ratios from u64 period and
runtime values, but it returns unsigned long.  tg_rt_schedulable() also
stores the current group limit and the accumulated child sum in unsigned
long.

On 32-bit builds, large bandwidth ratios can be truncated and the RT
group sum can wrap when enough siblings are present.  That can let an
overcommitted RT hierarchy pass the schedulability check, and it also
narrows the helper result for other callers.

Return u64 from to_ratio() and use u64 for the RT group totals so
bandwidth ratios are preserved and compared at full width on both 32-bit
and 64-bit builds.

Fixes: b40b2e8eb521 ("sched: rt: multi level group constraints")
Assisted-by: Codex:GPT-5
Signed-off-by: Joseph Salisbury <joseph.salisbury@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260403210014.2713404-1-joseph.salisbury@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched/debug: Fix avg_vruntime() usage 2026-04-27T13:27:29+00:00 Peter Zijlstra peterz@infradead.org 2026-04-01T13:20:21+00:00 28f77fca444977a8ea4c93e1008b424137098e7d commit e08d007f9d813616ce7093600bc4fdb9c9d81d89 upstream. John reported that stress-ng-yield could make his machine unhappy and managed to bisect it to commit b3d99f43c72b ("sched/fair: Fix zero_vruntime tracking"). The commit in question changes avg_vruntime() from a function that is a pure reader, to a function that updates variables. This turns an unlocked sched/debug usage of this function from a minor mistake into a data corruptor. Fixes: af4cf40470c2 ("sched/fair: Add cfs_rq::avg_vruntime") Fixes: b3d99f43c72b ("sched/fair: Fix zero_vruntime tracking") Reported-by: John Stultz <jstultz@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Tested-by: John Stultz <jstultz@google.com> Link: https://patch.msgid.link/20260401132355.196370805@infradead.org Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e08d007f9d813616ce7093600bc4fdb9c9d81d89 upstream.

John reported that stress-ng-yield could make his machine unhappy and
managed to bisect it to commit b3d99f43c72b ("sched/fair: Fix
zero_vruntime tracking").

The commit in question changes avg_vruntime() from a function that is
a pure reader, to a function that updates variables. This turns an
unlocked sched/debug usage of this function from a minor mistake into
a data corruptor.

Fixes: af4cf40470c2 ("sched/fair: Add cfs_rq::avg_vruntime")
Fixes: b3d99f43c72b ("sched/fair: Fix zero_vruntime tracking")
Reported-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260401132355.196370805@infradead.org
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dma-debug: Allow multiple invocations of overlapping entries 2026-04-22T11:22:33+00:00 Leon Romanovsky leonro@nvidia.com 2026-03-16T19:06:45+00:00 c2d109c982e925d9e67e268604b3e9495541b912 commit eca58535b154e6951327319afda94ac80eae7dc3 upstream. Repeated DMA mappings with DMA_ATTR_CPU_CACHE_CLEAN trigger the following splat. This prevents using the attribute in cases where a DMA region is shared and reused more than seven times. ------------[ cut here ]------------ DMA-API: exceeded 7 overlapping mappings of cacheline 0x000000000438c440 WARNING: kernel/dma/debug.c:467 at add_dma_entry+0x219/0x280, CPU#4: ibv_rc_pingpong/1644 Modules linked in: xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay mlx5_fwctl zram zsmalloc mlx5_ib fuse rpcrdma rdma_ucm ib_uverbs ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_core ib_core CPU: 4 UID: 2733 PID: 1644 Comm: ibv_rc_pingpong Not tainted 6.19.0+ #129 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:add_dma_entry+0x221/0x280 Code: c0 0f 84 f2 fe ff ff 83 e8 01 89 05 6d 99 11 01 e9 e4 fe ff ff 0f 8e 1f ff ff ff 48 8d 3d 07 ef 2d 01 be 07 00 00 00 48 89 e2 <67> 48 0f b9 3a e9 06 ff ff ff 48 c7 c7 98 05 2b 82 c6 05 72 92 28 RSP: 0018:ff1100010e657970 EFLAGS: 00010002 RAX: 0000000000000007 RBX: ff1100010234eb00 RCX: 0000000000000000 RDX: ff1100010e657970 RSI: 0000000000000007 RDI: ffffffff82678660 RBP: 000000000438c440 R08: 0000000000000228 R09: 0000000000000000 R10: 00000000000001be R11: 000000000000089d R12: 0000000000000800 R13: 00000000ffffffef R14: 0000000000000202 R15: ff1100010234eb00 FS: 00007fb15f3f6740(0000) GS:ff110008dcc19000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb15f32d3a0 CR3: 0000000116f59001 CR4: 0000000000373eb0 Call Trace: <TASK> debug_dma_map_sg+0x1b4/0x390 __dma_map_sg_attrs+0x6d/0x1a0 dma_map_sgtable+0x19/0x30 ib_umem_get+0x284/0x3b0 [ib_uverbs] mlx5_ib_reg_user_mr+0x68/0x2a0 [mlx5_ib] ib_uverbs_reg_mr+0x17f/0x2a0 [ib_uverbs] ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xc2/0x130 [ib_uverbs] ib_uverbs_cmd_verbs+0xa0b/0xae0 [ib_uverbs] ? ib_uverbs_handler_UVERBS_METHOD_QUERY_PORT_SPEED+0xe0/0xe0 [ib_uverbs] ? mmap_region+0x7a/0xb0 ? do_mmap+0x3b8/0x5c0 ib_uverbs_ioctl+0xa7/0x110 [ib_uverbs] __x64_sys_ioctl+0x14f/0x8b0 ? ksys_mmap_pgoff+0xc5/0x190 do_syscall_64+0x8c/0xbf0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7fb15f5e4eed Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00 RSP: 002b:00007ffe09a5c540 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffe09a5c5d0 RCX: 00007fb15f5e4eed RDX: 00007ffe09a5c5f0 RSI: 00000000c0181b01 RDI: 0000000000000003 RBP: 00007ffe09a5c590 R08: 0000000000000028 R09: 00007ffe09a5c794 R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffe09a5c794 R13: 000000000000000c R14: 0000000025a49170 R15: 000000000000000c </TASK> ---[ end trace 0000000000000000 ]--- Fixes: 61868dc55a11 ("dma-mapping: add DMA_ATTR_CPU_CACHE_CLEAN") Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/20260316-dma-debug-overlap-v3-1-1dde90a7f08b@nvidia.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit eca58535b154e6951327319afda94ac80eae7dc3 upstream.

Repeated DMA mappings with DMA_ATTR_CPU_CACHE_CLEAN trigger the
following splat. This prevents using the attribute in cases where a DMA
region is shared and reused more than seven times.

 ------------[ cut here ]------------
 DMA-API: exceeded 7 overlapping mappings of cacheline 0x000000000438c440
 WARNING: kernel/dma/debug.c:467 at add_dma_entry+0x219/0x280, CPU#4: ibv_rc_pingpong/1644
 Modules linked in: xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat nf_nat xt_addrtype br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay mlx5_fwctl zram zsmalloc mlx5_ib fuse rpcrdma rdma_ucm ib_uverbs ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_core ib_core
 CPU: 4 UID: 2733 PID: 1644 Comm: ibv_rc_pingpong Not tainted 6.19.0+ #129 PREEMPT
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 RIP: 0010:add_dma_entry+0x221/0x280
 Code: c0 0f 84 f2 fe ff ff 83 e8 01 89 05 6d 99 11 01 e9 e4 fe ff ff 0f 8e 1f ff ff ff 48 8d 3d 07 ef 2d 01 be 07 00 00 00 48 89 e2 <67> 48 0f b9 3a e9 06 ff ff ff 48 c7 c7 98 05 2b 82 c6 05 72 92 28
 RSP: 0018:ff1100010e657970 EFLAGS: 00010002
 RAX: 0000000000000007 RBX: ff1100010234eb00 RCX: 0000000000000000
 RDX: ff1100010e657970 RSI: 0000000000000007 RDI: ffffffff82678660
 RBP: 000000000438c440 R08: 0000000000000228 R09: 0000000000000000
 R10: 00000000000001be R11: 000000000000089d R12: 0000000000000800
 R13: 00000000ffffffef R14: 0000000000000202 R15: ff1100010234eb00
 FS:  00007fb15f3f6740(0000) GS:ff110008dcc19000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007fb15f32d3a0 CR3: 0000000116f59001 CR4: 0000000000373eb0
 Call Trace:
  <TASK>
  debug_dma_map_sg+0x1b4/0x390
  __dma_map_sg_attrs+0x6d/0x1a0
  dma_map_sgtable+0x19/0x30
  ib_umem_get+0x284/0x3b0 [ib_uverbs]
  mlx5_ib_reg_user_mr+0x68/0x2a0 [mlx5_ib]
  ib_uverbs_reg_mr+0x17f/0x2a0 [ib_uverbs]
  ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xc2/0x130 [ib_uverbs]
  ib_uverbs_cmd_verbs+0xa0b/0xae0 [ib_uverbs]
  ? ib_uverbs_handler_UVERBS_METHOD_QUERY_PORT_SPEED+0xe0/0xe0 [ib_uverbs]
  ? mmap_region+0x7a/0xb0
  ? do_mmap+0x3b8/0x5c0
  ib_uverbs_ioctl+0xa7/0x110 [ib_uverbs]
  __x64_sys_ioctl+0x14f/0x8b0
  ? ksys_mmap_pgoff+0xc5/0x190
  do_syscall_64+0x8c/0xbf0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53
 RIP: 0033:0x7fb15f5e4eed
 Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
 RSP: 002b:00007ffe09a5c540 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 00007ffe09a5c5d0 RCX: 00007fb15f5e4eed
 RDX: 00007ffe09a5c5f0 RSI: 00000000c0181b01 RDI: 0000000000000003
 RBP: 00007ffe09a5c590 R08: 0000000000000028 R09: 00007ffe09a5c794
 R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffe09a5c794
 R13: 000000000000000c R14: 0000000025a49170 R15: 000000000000000c
  </TASK>
 ---[ end trace 0000000000000000 ]---

Fixes: 61868dc55a11 ("dma-mapping: add DMA_ATTR_CPU_CACHE_CLEAN")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260316-dma-debug-overlap-v3-1-1dde90a7f08b@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched/deadline: Use revised wakeup rule for dl_server 2026-04-22T11:22:24+00:00 Peter Zijlstra peterz@infradead.org 2026-04-04T10:22:44+00:00 66dfc9179b78a8d20889063ebcd86a911f0d16b7 [ Upstream commit 14a857056466be9d3d907a94e92a704ac1be149b ] John noted that commit 115135422562 ("sched/deadline: Fix 'stuck' dl_server") unfixed the issue from commit a3a70caf7906 ("sched/deadline: Fix dl_server behaviour"). The issue in commit 115135422562 was for wakeups of the server after the deadline; in which case you *have* to start a new period. The case for a3a70caf7906 is wakeups before the deadline. Now, because the server is effectively running a least-laxity policy, it means that any wakeup during the runnable phase means dl_entity_overflow() will be true. This means we need to adjust the runtime to allow it to still run until the existing deadline expires. Use the revised wakeup rule for dl_defer entities. Fixes: 115135422562 ("sched/deadline: Fix 'stuck' dl_server") Reported-by: John Stultz <jstultz@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@redhat.com> Tested-by: John Stultz <jstultz@google.com> Link: https://patch.msgid.link/20260404102244.GB22575@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 14a857056466be9d3d907a94e92a704ac1be149b ]

John noted that commit 115135422562 ("sched/deadline: Fix 'stuck' dl_server")
unfixed the issue from commit a3a70caf7906 ("sched/deadline: Fix dl_server
behaviour").

The issue in commit 115135422562 was for wakeups of the server after the
deadline; in which case you *have* to start a new period. The case for
a3a70caf7906 is wakeups before the deadline.

Now, because the server is effectively running a least-laxity policy, it means
that any wakeup during the runnable phase means dl_entity_overflow() will be
true. This means we need to adjust the runtime to allow it to still run until
the existing deadline expires.

Use the revised wakeup rule for dl_defer entities.

Fixes: 115135422562 ("sched/deadline: Fix 'stuck' dl_server")
Reported-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Tested-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260404102244.GB22575@noisy.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
tracing/probe: reject non-closed empty immediate strings 2026-04-22T11:22:20+00:00 Pengpeng Hou pengpeng@iscas.ac.cn 2026-04-01T16:03:15+00:00 7dad8bf14346c76d3644a22c00372d1664ba1c15 [ Upstream commit 4346be6577aaa04586167402ae87bbdbe32484a4 ] parse_probe_arg() accepts quoted immediate strings and passes the body after the opening quote to __parse_imm_string(). That helper currently computes strlen(str) and immediately dereferences str[len - 1], which underflows when the body is empty and not closed with double-quotation. Reject empty non-closed immediate strings before checking for the closing quote. Link: https://lore.kernel.org/all/20260401160315.88518-1-pengpeng@iscas.ac.cn/ Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support") Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4346be6577aaa04586167402ae87bbdbe32484a4 ]

parse_probe_arg() accepts quoted immediate strings and passes the body
after the opening quote to __parse_imm_string(). That helper currently
computes strlen(str) and immediately dereferences str[len - 1], which
underflows when the body is empty and not closed with double-quotation.

Reject empty non-closed immediate strings before checking for the closing quote.

Link: https://lore.kernel.org/all/20260401160315.88518-1-pengpeng@iscas.ac.cn/

Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>