Linux kernel is vulnerable to denial of service (DoS) attacks. This is because the bio_map_user_iov() and bio_unmap_user() in ‘block/bio.c’ do unbalanced pages refcounting if IO vector has small consecutive buffers belonging to the same page. bio_add_pc_page merges them into one, but the page reference is never dropped, causing memory leak.
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=95d78c28b5a85bacbc29b8dba7c04babb9b0d467
seclists.org/oss-sec/2017/q4/52
www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.8
www.securityfocus.com/bid/101911
access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/7.5_Release_Notes/index.html
access.redhat.com/errata/RHSA-2018:0654
access.redhat.com/errata/RHSA-2018:0676
access.redhat.com/errata/RHSA-2018:1062
access.redhat.com/errata/RHSA-2018:1854
access.redhat.com/errata/RHSA-2019:1170
access.redhat.com/errata/RHSA-2019:1190
access.redhat.com/security/cve/CVE-2017-12190
access.redhat.com/security/cve/CVE-2017-13305
access.redhat.com/security/cve/CVE-2017-15274
access.redhat.com/security/updates/classification/#important
bugzilla.redhat.com/show_bug.cgi?id=1292927
bugzilla.redhat.com/show_bug.cgi?id=1401061
bugzilla.redhat.com/show_bug.cgi?id=1430418
bugzilla.redhat.com/show_bug.cgi?id=1448770
bugzilla.redhat.com/show_bug.cgi?id=1452589
bugzilla.redhat.com/show_bug.cgi?id=1462329
bugzilla.redhat.com/show_bug.cgi?id=1495089
bugzilla.redhat.com/show_bug.cgi?id=1500894
bugzilla.redhat.com/show_bug.cgi?id=1503749
bugzilla.redhat.com/show_bug.cgi?id=1506255
bugzilla.redhat.com/show_bug.cgi?id=1507270
bugzilla.redhat.com/show_bug.cgi?id=1509264
bugzilla.redhat.com/show_bug.cgi?id=1518274
bugzilla.redhat.com/show_bug.cgi?id=1518638
github.com/torvalds/linux/commit/2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058
github.com/torvalds/linux/commit/95d78c28b5a85bacbc29b8dba7c04babb9b0d467
lists.debian.org/debian-lts-announce/2017/12/msg00004.html
support.f5.com/csp/article/K93472064?utm_source=f5support&%3Butm_medium=RSS
usn.ubuntu.com/3582-1/
usn.ubuntu.com/3582-2/
usn.ubuntu.com/3583-1/
usn.ubuntu.com/3583-2/