CVS commit: src/sys/uvm

["YAMAMOTO Takashi" <yamt%netbsd.org@localhost>]

Module Name:    src
Committed By:   yamt
Date:           Sat Mar 21 03:17:25 UTC 2026

Modified Files:
        src/sys/uvm: uvm_mmap.c

Log Message:
sys_mincore: stop locking potentially huge amount of user memory

the current implementation performs uvm_vslock() on the
user-specified amount of memory. it isn't safe in general.
some might even consider it as a security issue.

this commit fixes it by splitting the user-specified range into
small ones which a temporary kernel buffer can cover. it's ok to
report potentially stale values as the mincore() api is inherently
racy in the first place.

while we still ought to invent a proper "lock user memory for
direct i/o" infrastructue, in this particular use case, it isn't
necessary or appropriate.


To generate a diff of this commit:
cvs rdiff -u -r1.188 -r1.189 src/sys/uvm/uvm_mmap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.