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while running ipmi, ipmi_smi_watcher_register() caused a suspicious RCU usage warning. ----- ============================= WARNING: suspicious RCU usage 5.10.0-rc3+ #1 Not tainted ----------------------------- drivers/char/ipmi/ipmi_msghandler.c:750 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-executor.0/4254: stack backtrace: CPU: 0 PID: 4254 Comm: syz-executor.0 Not tainted 5.10.0-rc3+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/ 01/2014 Call Trace: dump_stack+0x19d/0x200 ipmi_smi_watcher_register+0x2d3/0x340 [ipmi_msghandler] acpi_ipmi_init+0xb1/0x1000 [acpi_ipmi] do_one_initcall+0x149/0x7e0 do_init_module+0x1ef/0x700 load_module+0x3467/0x4140 __do_sys_finit_module+0x10d/0x1a0 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x468ded ----- It is safe because smi_watchers_mutex is locked and srcu_read_lock has been used, so simply pass lockdep_is_held() to the list_for_each_entry_rcu() to suppress this warning. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com> Message-Id: <20201119070839.381-1-miaoqinglang@huawei.com> Signed-off-by: Corey Minyard <cminyard@mvista.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.