Messages in this thread | | | Date | Wed, 30 Jun 2021 10:57:46 +0200 | From | Petr Mladek <> | Subject | Re: [PATCH] printk/console: Check consistent sequence number when handling race in console_unlock() |
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On Tue 2021-06-29 22:59:57, John Ogness wrote: > On 2021-06-30, kernel test robot <lkp@intel.com> wrote: > >>> kernel/printk/printk.c:2548:6: warning: variable 'next_seq' set but not used [-Wunused-but-set-variable] > > I suppose the correct fix for this warning would be to change the NOP > macros. Currently they are: > > #define prb_read_valid(rb, seq, r) false > #define prb_first_valid_seq(rb) 0 > > They should probably be something like (untested): > > #define prb_read_valid(rb, seq, r) \ > ({ \ > (void)(rb); \ > (void)(seq); \ > (void)(r); \ > false; \ > })
This did not work:
kernel/printk/printk.c: In function ‘console_unlock’: kernel/printk/printk.c:2600:23: error: ‘prb’ undeclared (first use in this function) if (!prb_read_valid(prb, console_seq, &r)) ^ kernel/printk/printk.c:2230:16: note: in definition of macro ‘prb_read_valid’ (void)(rb); \ ^~ kernel/printk/printk.c:2600:23: note: each undeclared identifier is reported only once for each function it appears in if (!prb_read_valid(prb, console_seq, &r)) ^ kernel/printk/printk.c:2230:16: note: in definition of macro ‘prb_read_valid’ (void)(rb); \ ^~
Instead, it might be solved by declaring next_seq as:
u64 __maybe_unused next_seq;
Any better idea is welcome. Well, it is not worth any big complexity.
Best Regards, Petr
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