Merge branch 'net-drop_monitor-fix-concurrency-issues-preemption-warning-and-buffer-overrun'

Eric Dumazet says:

====================
net: drop_monitor: fix concurrency issues, preemption warning, and buffer overrun

This series addresses several issues discovered in the drop_monitor subsystem:

Patch 1 adds missing tracepoint unregistration synchronization to the
net_dm_trace_on_set() error unwind path, preventing in-flight probes
from scheduling work after the module reference has been dropped.

Patch 2 resolves a race condition during monitoring teardown where per-CPU
timers can be re-armed after deletion if a concurrent worker encounters a
memory allocation failure, switching to timer_shutdown_sync().

Patch 3 fixes a CONFIG_DEBUG_PREEMPT warning reported by syzbot when
kfree_skb() is invoked from preemptible process context, using raw_cpu_ptr()
since each per-CPU queue is safely protected by its own spinlock.

Patch 4 fixes an out-of-bounds write in reset_per_cpu_data() where memset()
overwrote the allocated SKB tailroom by sizeof(struct nlattr) bytes.
====================

Link: https://patch.msgid.link/20260910204612.3762015-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>