linux.git/kernel/time/itimer.c, branch v6.12.80 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git time: Prevent undefined behaviour in timespec64_to_ns() 2020-10-26T10:48:11+00:00 Zeng Tao prime.zeng@hisilicon.com 2020-09-01T09:30:13+00:00 cb47755725da7b90fecbb2aa82ac3b24a7adb89b UBSAN reports: Undefined behaviour in ./include/linux/time64.h:127:27 signed integer overflow: 17179869187 * 1000000000 cannot be represented in type 'long long int' Call Trace: timespec64_to_ns include/linux/time64.h:127 [inline] set_cpu_itimer+0x65c/0x880 kernel/time/itimer.c:180 do_setitimer+0x8e/0x740 kernel/time/itimer.c:245 __x64_sys_setitimer+0x14c/0x2c0 kernel/time/itimer.c:336 do_syscall_64+0xa1/0x540 arch/x86/entry/common.c:295 Commit bd40a175769d ("y2038: itimer: change implementation to timespec64") replaced the original conversion which handled time clamping correctly with timespec64_to_ns() which has no overflow protection. Fix it in timespec64_to_ns() as this is not necessarily limited to the usage in itimers. [ tglx: Added comment and adjusted the fixes tag ] Fixes: 361a3bf00582 ("time64: Add time64.h header and define struct timespec64") Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1598952616-6416-1-git-send-email-prime.zeng@hisilicon.com 
UBSAN reports:

Undefined behaviour in ./include/linux/time64.h:127:27
signed integer overflow:
17179869187 * 1000000000 cannot be represented in type 'long long int'
Call Trace:
 timespec64_to_ns include/linux/time64.h:127 [inline]
 set_cpu_itimer+0x65c/0x880 kernel/time/itimer.c:180
 do_setitimer+0x8e/0x740 kernel/time/itimer.c:245
 __x64_sys_setitimer+0x14c/0x2c0 kernel/time/itimer.c:336
 do_syscall_64+0xa1/0x540 arch/x86/entry/common.c:295

Commit bd40a175769d ("y2038: itimer: change implementation to timespec64")
replaced the original conversion which handled time clamping correctly with
timespec64_to_ns() which has no overflow protection.

Fix it in timespec64_to_ns() as this is not necessarily limited to the
usage in itimers.

[ tglx: Added comment and adjusted the fixes tag ]

Fixes: 361a3bf00582 ("time64: Add time64.h header and define struct timespec64")
Signed-off-by: Zeng Tao <prime.zeng@hisilicon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1598952616-6416-1-git-send-email-prime.zeng@hisilicon.com
y2038: rename itimerval to __kernel_old_itimerval 2019-12-18T17:07:33+00:00 Arnd Bergmann arnd@arndb.de 2019-11-15T14:53:29+00:00 4f9fbd893fe83a1193adceca41c8f7aa6c7382a1 Take the renaming of timeval and timespec one level further, also renaming itimerval to __kernel_old_itimerval, to avoid namespace conflicts with the user-space structure that may use 64-bit time_t members. Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
Take the renaming of timeval and timespec one level further,
also renaming itimerval to __kernel_old_itimerval, to avoid
namespace conflicts with the user-space structure that may
use 64-bit time_t members.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
y2038: alarm: fix half-second cut-off 2019-11-25T20:52:35+00:00 Arnd Bergmann arnd@arndb.de 2019-11-25T20:25:46+00:00 b111df8447acdeb4b9220f99d5d4b28f83eb56ad Changing alarm_itimer accidentally broke the logic for arithmetic rounding of half seconds in the return code. Change it to a constant based on NSEC_PER_SEC, as suggested by Ben Hutchings. Fixes: bd40a175769d ("y2038: itimer: change implementation to timespec64") Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
Changing alarm_itimer accidentally broke the logic for arithmetic
rounding of half seconds in the return code.

Change it to a constant based on NSEC_PER_SEC, as suggested by
Ben Hutchings.

Fixes: bd40a175769d ("y2038: itimer: change implementation to timespec64")
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
y2038: itimer: change implementation to timespec64 2019-11-15T13:38:30+00:00 Arnd Bergmann arnd@arndb.de 2019-11-07T14:27:39+00:00 bd40a175769d411b2a37e1c087082ac7ee2c15bb There is no 64-bit version of getitimer/setitimer since that is not actually needed. However, the implementation is built around the deprecated 'struct timeval' type. Change the code to use timespec64 internally to reduce the dependencies on timeval and associated helper functions. Minor adjustments in the code are needed to make the native and compat version work the same way, and to keep the range check working after the conversion. Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
There is no 64-bit version of getitimer/setitimer since that is not
actually needed. However, the implementation is built around the
deprecated 'struct timeval' type.

Change the code to use timespec64 internally to reduce the dependencies
on timeval and associated helper functions.

Minor adjustments in the code are needed to make the native and compat
version work the same way, and to keep the range check working after
the conversion.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
y2038: move itimer reset into itimer.c 2019-11-15T13:38:30+00:00 Arnd Bergmann arnd@arndb.de 2019-10-25T19:37:43+00:00 ddbc7d0657e9fd38b69f16bd0310703367b52d29 Preparing for a change to the itimer internals, stop using the do_setitimer() symbol and instead use a new higher-level interface. The do_getitimer()/do_setitimer functions can now be made static, allowing the compiler to potentially produce better object code. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
Preparing for a change to the itimer internals, stop using the
do_setitimer() symbol and instead use a new higher-level interface.

The do_getitimer()/do_setitimer functions can now be made static,
allowing the compiler to potentially produce better object code.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
y2038: use compat_{get,set}_itimer on alpha 2019-11-15T13:38:30+00:00 Arnd Bergmann arnd@arndb.de 2019-10-25T14:59:39+00:00 4c22ea2b91203564fdf392b3d3cae249b652a8ae The itimer handling for the old alpha osf_setitimer/osf_getitimer system calls is identical to the compat version of getitimer/setitimer, so just use those directly. Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
The itimer handling for the old alpha osf_setitimer/osf_getitimer
system calls is identical to the compat version of getitimer/setitimer,
so just use those directly.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
y2038: itimer: compat handling to itimer.c 2019-11-15T13:38:30+00:00 Arnd Bergmann arnd@arndb.de 2019-10-25T08:46:22+00:00 c1745f84be2657f5702388133551b759b9237f59 The structure is only used in one place, moving it there simplifies the interface and helps with later changes to this code. Rename it to match the other time32 structures in the process. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
The structure is only used in one place, moving it there simplifies the
interface and helps with later changes to this code.

Rename it to match the other time32 structures in the process.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
posix-cpu-timers: Switch thread group sampling to array 2019-08-28T09:50:39+00:00 Thomas Gleixner tglx@linutronix.de 2019-08-21T19:09:16+00:00 b7be4ef1365dcb56fdffc6689e41058b23f5996d That allows more simplifications in various places. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lkml.kernel.org/r/20190821192921.988426956@linutronix.de 
That allows more simplifications in various places.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.988426956@linutronix.de
itimers: Use quick sample function 2019-08-28T09:50:26+00:00 Thomas Gleixner tglx@linutronix.de 2019-08-21T19:08:52+00:00 a34360d42434bbf28c0f375444c52c154ae3e6cf get_itimer() locks sighand lock and checks whether the timer is already expired. If it is not expired then the thread group cputime accounting is already enabled. Use the sampling function not the one which is meant for starting a timer. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lkml.kernel.org/r/20190821192919.689713638@linutronix.de 
get_itimer() locks sighand lock and checks whether the timer is already
expired. If it is not expired then the thread group cputime accounting is
already enabled. Use the sampling function not the one which is meant for
starting a timer.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.689713638@linutronix.de
itimers: Prepare for PREEMPT_RT 2019-08-01T18:51:24+00:00 Anna-Maria Gleixner anna-maria@linutronix.de 2019-07-30T22:33:51+00:00 c7e6d704a0097e59667495cf52dcc4e1085e620b Use the hrtimer_cancel_wait_running() synchronization mechanism to prevent priority inversion and live locks on PREEMPT_RT. As a benefit the retry loop gains the missing cpu_relax() on !RT. [ tglx: Split out of combo patch ] Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20190730223828.690771827@linutronix.de 
Use the hrtimer_cancel_wait_running() synchronization mechanism to prevent
priority inversion and live locks on PREEMPT_RT.

As a benefit the retry loop gains the missing cpu_relax() on !RT.

[ tglx: Split out of combo patch ]

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190730223828.690771827@linutronix.de