| Message ID | 20231003194547.2237424-5-axelrasmussen@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | userfaultfd man page updates | expand |
Hi Axel, On Tue, Oct 03, 2023 at 12:45:46PM -0700, Axel Rasmussen wrote: > The list of error codes in the man page was out of date with respect to > the current state of the kernel. Some errors were partially / > incorrectly described. > > Update the error code listing, so it matches the current state of the > kernel, and correctly describes all the errors. > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> > --- > man2/ioctl_userfaultfd.2 | 37 +++++++++++++++++++++---------------- > 1 file changed, 21 insertions(+), 16 deletions(-) > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > index 2ee6a0532..95d69f773 100644 > --- a/man2/ioctl_userfaultfd.2 > +++ b/man2/ioctl_userfaultfd.2 > @@ -388,12 +388,6 @@ On error, \-1 is returned and > .I errno > is set to indicate the error. > Possible errors include: > -.\" FIXME Is the following error list correct? > -.\" > -.TP > -.B EBUSY > -A mapping in the specified range is registered with another > -userfaultfd object. > .TP > .B EFAULT > .I argp > @@ -408,21 +402,32 @@ field; or the > field was zero. > .TP > .B EINVAL > -There is no mapping in the specified address range. > -.TP > -.B EINVAL > +The specified address range was invalid. > +More specifically, > +no mapping exists in the given range, > +or the mapping that exists there is invalid > +(e.g. unsupported type of memory), > +or the range values ( This produces some unwanted space. Please apply the following fix to your patch. diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 index 6e954e98c..795014794 100644 --- a/man2/ioctl_userfaultfd.2 +++ b/man2/ioctl_userfaultfd.2 @@ -432,11 +432,11 @@ .SS UFFDIO_REGISTER no mapping exists in the given range, or the mapping that exists there is invalid (e.g. unsupported type of memory), -or the range values ( -.I range.start +or the range values +.IR ( range.start or -.I range.len -) are not multiples of the relevant page size, +.IR range.len ) +are not multiples of the relevant page size, or .I range.len is zero. > .I range.start > or > .I range.len > -is not a multiple of the system page size; or, > +) are not multiples of the relevant page size, > +or > .I range.len > -is zero; or these fields are otherwise invalid. > +is zero. > .TP > -.B EINVAL > -There as an incompatible mapping in the specified address range. > -.\" Mike Rapoport: > -.\" ENOMEM if the process is exiting and the > -.\" mm_struct has gone by the time userfault grabs it. > +.B ENOMEM > +The process is exiting, > +and its address space has already been torn down > +when userfaultfd attempts to reference it. > +.TP > +.B EPERM > +The userfaultfd would allow writing to a file backing the mapping, > +but the calling process lacks such write permissions. > +.TP > +.B EBUSY > +A mapping in the specified range is registered with another > +userfaultfd object. Why would you move EBUSY to the end? Do you see any reasons to order it that way? Thanks, Alex > .SS UFFDIO_UNREGISTER > (Since Linux 4.3.) > Unregister a memory address range from userfaultfd. > -- > 2.42.0.609.gbb76f46606-goog >
Hi! On Mon, 2023-10-09 at 00:06:48 +0200, Alejandro Colomar wrote: > This produces some unwanted space. Please apply the following fix to > your patch. > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > index 6e954e98c..795014794 100644 > --- a/man2/ioctl_userfaultfd.2 > +++ b/man2/ioctl_userfaultfd.2 > @@ -432,11 +432,11 @@ .SS UFFDIO_REGISTER > no mapping exists in the given range, > or the mapping that exists there is invalid > (e.g. unsupported type of memory), > -or the range values ( > -.I range.start > +or the range values > +.IR ( range.start I think you meant «.RI» here? > or > -.I range.len > -) are not multiples of the relevant page size, > +.IR range.len ) > +are not multiples of the relevant page size, > or > .I range.len > is zero. > Regards, Guillem
Hi Guillem! On Tue, Oct 17, 2023 at 11:23:10PM +0200, Guillem Jover wrote: > Hi! > > On Mon, 2023-10-09 at 00:06:48 +0200, Alejandro Colomar wrote: > > This produces some unwanted space. Please apply the following fix to > > your patch. > > > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > > index 6e954e98c..795014794 100644 > > --- a/man2/ioctl_userfaultfd.2 > > +++ b/man2/ioctl_userfaultfd.2 > > @@ -432,11 +432,11 @@ .SS UFFDIO_REGISTER > > no mapping exists in the given range, > > or the mapping that exists there is invalid > > (e.g. unsupported type of memory), > > -or the range values ( > > -.I range.start > > +or the range values > > +.IR ( range.start > > I think you meant «.RI» here? Yup! Good catch. Cheers, Alex > > > or > > -.I range.len > > -) are not multiples of the relevant page size, > > +.IR range.len ) > > +are not multiples of the relevant page size, > > or > > .I range.len > > is zero. > > > > Regards, > Guillem
On Tue, Oct 17, 2023 at 2:42 PM Alejandro Colomar <alx@kernel.org> wrote: > > Hi Guillem! > > On Tue, Oct 17, 2023 at 11:23:10PM +0200, Guillem Jover wrote: > > Hi! > > > > On Mon, 2023-10-09 at 00:06:48 +0200, Alejandro Colomar wrote: > > > This produces some unwanted space. Please apply the following fix to > > > your patch. > > > > > > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 > > > index 6e954e98c..795014794 100644 > > > --- a/man2/ioctl_userfaultfd.2 > > > +++ b/man2/ioctl_userfaultfd.2 > > > @@ -432,11 +432,11 @@ .SS UFFDIO_REGISTER > > > no mapping exists in the given range, > > > or the mapping that exists there is invalid > > > (e.g. unsupported type of memory), > > > -or the range values ( > > > -.I range.start > > > +or the range values > > > +.IR ( range.start > > > > I think you meant «.RI» here? > > Yup! Good catch. Thanks, I'll apply this change in a v3. > > Cheers, > Alex > > > > > > or > > > -.I range.len > > > -) are not multiples of the relevant page size, > > > +.IR range.len ) > > > +are not multiples of the relevant page size, > > > or > > > .I range.len > > > is zero. > > > > > > > Regards, > > Guillem Regarding the -EBUSY ordering, I did it this way because that's the order in which the conditions are checked in the code. But, I agree that isn't very obvious / useful to any reader of the man page :) and alphabetical order is preferred. I'll correct that in v3. > > -- > <https://www.alejandro-colomar.es/>
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2 index 2ee6a0532..95d69f773 100644 --- a/man2/ioctl_userfaultfd.2 +++ b/man2/ioctl_userfaultfd.2 @@ -388,12 +388,6 @@ On error, \-1 is returned and .I errno is set to indicate the error. Possible errors include: -.\" FIXME Is the following error list correct? -.\" -.TP -.B EBUSY -A mapping in the specified range is registered with another -userfaultfd object. .TP .B EFAULT .I argp @@ -408,21 +402,32 @@ field; or the field was zero. .TP .B EINVAL -There is no mapping in the specified address range. -.TP -.B EINVAL +The specified address range was invalid. +More specifically, +no mapping exists in the given range, +or the mapping that exists there is invalid +(e.g. unsupported type of memory), +or the range values ( .I range.start or .I range.len -is not a multiple of the system page size; or, +) are not multiples of the relevant page size, +or .I range.len -is zero; or these fields are otherwise invalid. +is zero. .TP -.B EINVAL -There as an incompatible mapping in the specified address range. -.\" Mike Rapoport: -.\" ENOMEM if the process is exiting and the -.\" mm_struct has gone by the time userfault grabs it. +.B ENOMEM +The process is exiting, +and its address space has already been torn down +when userfaultfd attempts to reference it. +.TP +.B EPERM +The userfaultfd would allow writing to a file backing the mapping, +but the calling process lacks such write permissions. +.TP +.B EBUSY +A mapping in the specified range is registered with another +userfaultfd object. .SS UFFDIO_UNREGISTER (Since Linux 4.3.) Unregister a memory address range from userfaultfd.
The list of error codes in the man page was out of date with respect to the current state of the kernel. Some errors were partially / incorrectly described. Update the error code listing, so it matches the current state of the kernel, and correctly describes all the errors. Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> --- man2/ioctl_userfaultfd.2 | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-)