Hi Lorenzo, Jann, > Subject: Re: [PATCH man-pages v4] madvise.2: add MADV_GUARD_INSTALL, MADV_GUARD_REMOVE description We use uppercase after the prefix, so s/add/Add/. On Thu, Dec 05, 2024 at 10:41:25AM +0000, Lorenzo Stoakes wrote: > Lightweight guard region support has been added to Linux 6.13, which adds > MADV_GUARD_INSTALL and MADV_GUARD_REMOVE flags to the madvise() system > call. Therefore, update the manpage for madvise() and describe these The right amount of inter-sentence space is two. See this: <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/CONTRIBUTING.d/patches/description?id=bcf7d00fa4c7ce270f07d6e347c01b1f1e37580f> <https://web.archive.org/web/20171217060354/http://www.heracliteanriver.com/?p=324> > operations. > > Reviewed-by: Jann Horn <jannh@xxxxxxxxxx> Thanks for the review! > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> Thanks for the patch! I've applied it, with some minor tweaks. See comments below. <https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=bb405ee3f6039226267fb1c6d2cb1fbb18d835bf> Here's the diff that I applied when amending your patch: diff --git i/man/man2/madvise.2 w/man/man2/madvise.2 index adb372424..fa24f6bf6 100644 --- i/man/man2/madvise.2 +++ w/man/man2/madvise.2 @@ -678,7 +678,8 @@ .SS Linux-specific advice values the process can be killed at any moment when the system runs out of memory. .TP .BR MADV_GUARD_INSTALL " (since Linux 6.13)" -Install a lightweight guard region into the range specified by +Install a lightweight guard region +into the range specified by .I addr and .IR size , @@ -686,22 +687,27 @@ .SS Linux-specific advice values .B SIGSEGV signal being raised. .IP -If the region maps memory pages they will be cleared as part of the operation, +If the region maps memory pages +they will be cleared as part of the operation, though if .B MADV_GUARD_INSTALL -is applied to regions containing pre-existing lightweight guard regions, +is applied to regions +containing pre-existing lightweight guard regions, they are left in place. .IP -This operation is only supported for writable anonymous private mappings which -have not been mlock'd. +This operation is supported +only for writable anonymous private mappings +which have not been mlock'd. An .B EINVAL error is returned if it is attempted on any other kind of mapping. .IP This operation is more efficient than mapping a new region of memory .BR PROT_NONE , -as it does not require the establishment of new mappings, -instead regions of an existing mapping simply have their page tables +as it does not require the establishment of new mappings. +Instead, +regions of an existing mapping +simply have their page tables manipulated to establish the desired behavior. No additional memory is used. .IP @@ -740,12 +746,15 @@ .SS Linux-specific advice values operation is applied to them. .TP .BR MADV_GUARD_REMOVE " (since Linux 6.13)" -Remove any lightweight guard regions which exist in the range specified by +Remove any lightweight guard regions +which exist in the range specified by .I addr and .IR size . .IP -All mappings in the range other than lightweight guard regions are left in place +All mappings in the range +other than lightweight guard regions +are left in place (including mlock'd mappings). The operation is, however, > --- > v4: > * Reference function chapters as per Alejandro. > * Minor rewording as per Alejandro. > > v3: > * Don't describe SIGSEGV as a fatal signal as per Jann. > https://lore.kernel.org/all/20241202165829.72121-1-lorenzo.stoakes@xxxxxxxxxx > > v2: > * Updated to use semantic newlines as suggested by Alejandro. I've broken lines a little bit more, even though they were correct, just for having shorter lines. > * Avoided emboldening parens as suggested by Alejandro. > * One very minor grammatical fix. > https://lore.kernel.org/all/20241129155943.85215-1-lorenzo.stoakes@xxxxxxxxxx > > v1: > https://lore.kernel.org/all/20241129093205.8664-1-lorenzo.stoakes@xxxxxxxxxx > > man/man2/madvise.2 | 93 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 93 insertions(+) > > diff --git a/man/man2/madvise.2 b/man/man2/madvise.2 > index 4f2210ee2..7d682fa40 100644 > --- a/man/man2/madvise.2 > +++ b/man/man2/madvise.2 > @@ -676,6 +676,91 @@ or secret memory regions created using > Note that with > .BR MADV_POPULATE_WRITE , > the process can be killed at any moment when the system runs out of memory. > +.TP > +.BR MADV_GUARD_INSTALL " (since Linux 6.13)" > +Install a lightweight guard region into the range specified by > +.I addr > +and > +.IR size , > +causing any read or write in the range to result in a > +.B SIGSEGV > +signal being raised. > +.IP > +If the region maps memory pages they will be cleared as part of the operation, > +though if > +.B MADV_GUARD_INSTALL > +is applied to regions containing pre-existing lightweight guard regions, > +they are left in place. > +.IP > +This operation is only supported for writable anonymous private mappings which I missed this before. It was the same misplacement of only. :) Have a lovely day! Alex -- <https://www.alejandro-colomar.es/>
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