Messages in this thread | | | Date | Tue, 23 Apr 2024 09:20:34 -0400 | Subject | Re: [PATCH] admin-guide/hw-vuln/core-scheduling: fix return type of PR_SCHED_CORE_GET | From | Chris Hyser <> |
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On 4/23/24 06:34, Thomas Weißschuh wrote:
> sched_core_share_pid() copies the cookie to userspace with > put_user(id, (u64 __user *)uaddr), expecting 64 bits of space. > The "unsigned long" datatype that is documented in core-scheduling.rst > however is only 32 bits large on 32 bit architectures. > > Document "unsigned long long" as the correct data type that is always > 64bits large. > > This matches what the selftest cs_prctl_test.c has been doing all along. > > Fixes: 0159bb020ca9 ("Documentation: Add usecases, design and interface for core scheduling") > Cc: stable@vger.kernel.org > Link: https://lore.kernel.org/util-linux/df7a25a0-7923-4f8b-a527-5e6f0064074d@t-8ch.de/ > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> > --- > Documentation/admin-guide/hw-vuln/core-scheduling.rst | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/hw-vuln/core-scheduling.rst b/Documentation/admin-guide/hw-vuln/core-scheduling.rst > index cf1eeefdfc32..a92e10ec402e 100644 > --- a/Documentation/admin-guide/hw-vuln/core-scheduling.rst > +++ b/Documentation/admin-guide/hw-vuln/core-scheduling.rst > @@ -67,8 +67,8 @@ arg4: > will be performed for all tasks in the task group of ``pid``. > > arg5: > - userspace pointer to an unsigned long for storing the cookie returned by > - ``PR_SCHED_CORE_GET`` command. Should be 0 for all other commands. > + userspace pointer to an unsigned long long for storing the cookie returned > + by ``PR_SCHED_CORE_GET`` command. Should be 0 for all other commands. >
Yes you're right, that is what the test code actually does.
Reviewed-by: Chris Hyser <chris.hyser@oracle.com>
> In order for a process to push a cookie to, or pull a cookie from a process, it > is required to have the ptrace access mode: `PTRACE_MODE_READ_REALCREDS` to the > > --- > base-commit: 71b1543c83d65af8215d7558d70fc2ecbee77dcf > change-id: 20240423-core-scheduling-cookie-b0551c40b086 > > Best regards,
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