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Hangbin Liu says: ==================== hsr: fix lock warnings hsr_for_each_port is called in many places without holding the RCU read lock, this may trigger warnings on debug kernels like: [ 40.457015] [ T201] WARNING: suspicious RCU usage [ 40.457020] [ T201] 6.17.0-rc2-virtme #1 Not tainted [ 40.457025] [ T201] ----------------------------- [ 40.457029] [ T201] net/hsr/hsr_main.c:137 RCU-list traversed in non-reader section!! [ 40.457036] [ T201] other info that might help us debug this: [ 40.457040] [ T201] rcu_scheduler_active = 2, debug_locks = 1 [ 40.457045] [ T201] 2 locks held by ip/201: [ 40.457050] [ T201] #0: ffffffff93040a40 (&ops->srcu){.+.+}-{0:0}, at: rtnl_link_ops_get+0xf2/0x280 [ 40.457080] [ T201] #1: ffffffff92e7f968 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x5e1/0xb20 [ 40.457102] [ T201] stack backtrace: [ 40.457108] [ T201] CPU: 2 UID: 0 PID: 201 Comm: ip Not tainted 6.17.0-rc2-virtme #1 PREEMPT(full) [ 40.457114] [ T201] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 40.457117] [ T201] Call Trace: [ 40.457120] [ T201] <TASK> [ 40.457126] [ T201] dump_stack_lvl+0x6f/0xb0 [ 40.457136] [ T201] lockdep_rcu_suspicious.cold+0x4f/0xb1 [ 40.457148] [ T201] hsr_port_get_hsr+0xfe/0x140 [ 40.457158] [ T201] hsr_add_port+0x192/0x940 [ 40.457167] [ T201] ? __pfx_hsr_add_port+0x10/0x10 [ 40.457176] [ T201] ? lockdep_init_map_type+0x5c/0x270 [ 40.457189] [ T201] hsr_dev_finalize+0x4bc/0xbf0 [ 40.457204] [ T201] hsr_newlink+0x3c3/0x8f0 [ 40.457212] [ T201] ? __pfx_hsr_newlink+0x10/0x10 [ 40.457222] [ T201] ? rtnl_create_link+0x173/0xe40 [ 40.457233] [ T201] rtnl_newlink_create+0x2cf/0x750 [ 40.457243] [ T201] ? __pfx_rtnl_newlink_create+0x10/0x10 [ 40.457247] [ T201] ? __dev_get_by_name+0x12/0x50 [ 40.457252] [ T201] ? rtnl_dev_get+0xac/0x140 [ 40.457259] [ T201] ? __pfx_rtnl_dev_get+0x10/0x10 [ 40.457285] [ T201] __rtnl_newlink+0x22c/0xa50 [ 40.457305] [ T201] rtnl_newlink+0x637/0xb20 Adding rcu_read_lock() for all hsr_for_each_port() looks confusing. Introduce a new helper, hsr_for_each_port_rtnl(), that assumes the RTNL lock is held. This allows callers in suitable contexts to iterate ports safely without explicit RCU locking. Other code paths that rely on RCU protection continue to use hsr_for_each_port() with rcu_read_lock(). ==================== Link: https://patch.msgid.link/20250905091533.377443-1-liuhangbin@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
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