iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ARM: Snapshot thread flags

Browse Source 
Some thread flags can be set remotely, and so even when IRQs are disabled,
the flags can change under our feet. Generally this is unlikely to cause a
problem in practice, but it is somewhat unsound, and KCSAN will
legitimately warn that there is a data race.

To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.

Convert them all to the new flag accessor helpers.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Link: https://lore.kernel.org/r/20211129130653.2037928-6-mark.rutland@arm.com
This commit is contained in:
Mark Rutland 2021-11-29 13:06:47 +00:00 committed by Thomas Gleixner
parent 7fb2b24bb5
commit 050e22bfc4
2 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm/kernel/signal.c
View File

@ -631,7 +631,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
}
}
local_irq_disable();
thread_flags = current_thread_info()->flags;
thread_flags = read_thread_flags();
} while (thread_flags & _TIF_WORK_MASK);
return 0;
}

2
arch/arm/mm/alignment.c
View File

@ -990,7 +990,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
* there is no work pending for this thread.
*/
raw_local_irq_disable();
if (!(current_thread_info()->flags & _TIF_WORK_MASK))
if (!(read_thread_flags() & _TIF_WORK_MASK))
set_cr(cr_no_alignment);
}