https://github.com/torvalds/linux
Revision bc81426f5beef7da863d3365bc9d45e820448745 authored by Michal Koutný on 01 June 2019, 05:30:19 UTC, committed by Linus Torvalds on 01 June 2019, 22:51:31 UTC
The commit a3b609ef9f8b ("proc read mm's {arg,env}_{start,end} with mmap semaphore taken.") added synchronization of reading argument/environment boundaries under mmap_sem. Later commit 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") avoided the coarse use of mmap_sem in similar situations. But there still remained two places that (mis)use mmap_sem. get_cmdline should also use arg_lock instead of mmap_sem when it reads the boundaries. The second place that should use arg_lock is in prctl_set_mm. By protecting the boundaries fields with the arg_lock, we can downgrade mmap_sem to reader lock (analogous to what we already do in prctl_set_mm_map). [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20190502125203.24014-3-mkoutny@suse.com Fixes: 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Co-developed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: bc81426f5beef7da863d3365bc9d45e820448745 authored by Michal Koutný on 01 June 2019, 05:30:19 UTC
prctl_set_mm: downgrade mmap_sem to read lock
prctl_set_mm: downgrade mmap_sem to read lock
Tip revision: bc81426
File | Mode | Size |
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Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 14.6 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 71 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.6 KB |
.mailmap | -rw-r--r-- | 11.9 KB |
COPYING | -rw-r--r-- | 423 bytes |
CREDITS | -rw-r--r-- | 96.9 KB |
Kbuild | -rw-r--r-- | 1.5 KB |
Kconfig | -rw-r--r-- | 563 bytes |
MAINTAINERS | -rw-r--r-- | 498.9 KB |
Makefile | -rw-r--r-- | 58.8 KB |
README | -rw-r--r-- | 727 bytes |
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