Catcrafts/milos-linux
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

rds: mark snapshot pages dirty in rds_info_getsockopt()

Browse source 
rds_info_getsockopt() pins the destination user pages with FOLL_WRITE and
the RDS_INFO_* producers memcpy the snapshot into them through
kmap_atomic(). Because that copy goes through the kernel direct map, the
dirty bit on the user PTE is never set, so unpin_user_pages() releases the
pages without marking them dirty. A file-backed destination page can then
be reclaimed without writeback, silently discarding the copied data.

Use unpin_user_pages_dirty_lock() with make_dirty=true so the modified
pages are marked dirty before they are unpinned.

Fixes: a8c879a7ee ("RDS: Info and stats")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Allison Henderson <achender@kernel.org>
Link: https://patch.msgid.link/20260608-rds_fix-v1-1-006c88543408@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Breno Leitao 2026-06-08 02:32:05 -07:00 • committed by Jakub Kicinski
commit 512db8267b
1 changed files with 1 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

2
net/rds/info.c
View file

@ -235,7 +235,7 @@ call_func:
out:
if (pages)
unpin_user_pages(pages, nr_pages);
unpin_user_pages_dirty_lock(pages, nr_pages, true);
kfree(pages);
return ret;