Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

-Wparentheses-equality in drivers/net/wireless/intel/ipw2x00/ipw2200.c #134

Closed
tpimh opened this issue Sep 20, 2018 · 3 comments
Closed

-Wparentheses-equality in drivers/net/wireless/intel/ipw2x00/ipw2200.c #134

tpimh opened this issue Sep 20, 2018 · 3 comments
Assignees
@nathanchance
Labels
-Wparentheses-equality [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] 4.20 This bug was fixed in Linux 4.20

Comments

@tpimh
Copy link

tpimh commented Sep 20, 2018 

drivers/net/wireless/intel/ipw2x00/ipw2200.c:5655:28: warning: equality comparison with
      extraneous parentheses [-Wparentheses-equality]
                if ((priv->ieee->iw_mode == IW_MODE_ADHOC)) {
                     ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
drivers/net/wireless/intel/ipw2x00/ipw2200.c:5655:28: note: remove extraneous parentheses
      around the comparison to silence this warning
                if ((priv->ieee->iw_mode == IW_MODE_ADHOC)) {
                    ~                    ^               ~
drivers/net/wireless/intel/ipw2x00/ipw2200.c:5655:28: note: use '=' to turn this equality
      comparison into an assignment
                if ((priv->ieee->iw_mode == IW_MODE_ADHOC)) {
                                         ^~
                                         =
1 warning generated.
@tpimh tpimh added [BUG] linux A bug that should be fixed in the mainline kernel. low priority This bug is not critical and not a priority -Wparentheses-equality labels Sep 20, 2018
@nathanchance
Copy link
Member

Patch sent: https://lore.kernel.org/lkml/20180920204548.2405-1-natechancellor@gmail.com/

@nathanchance nathanchance self-assigned this Sep 20, 2018
@nathanchance nathanchance added [PATCH] Exists There is a patch that fixes this issue [PATCH] Submitted A patch has been submitted for review and removed [PATCH] Exists There is a patch that fixes this issue labels Sep 20, 2018
fengguang pushed a commit to 0day-ci/linux that referenced this issue Sep 22, 2018
@nathanchance @intel-lab-lkp
wireless: ipw2x00: Remove unnecessary parentheses
cc7d86e 
Clang warns when multiple pairs of parentheses are used for a single
conditional statement.

drivers/net/wireless/intel/ipw2x00/ipw2200.c:5655:28: warning: equality
comparison with extraneous parentheses [-Wparentheses-equality]
                if ((priv->ieee->iw_mode == IW_MODE_ADHOC)) {
                     ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
drivers/net/wireless/intel/ipw2x00/ipw2200.c:5655:28: note: remove
extraneous parentheses around the comparison to silence this warning
                if ((priv->ieee->iw_mode == IW_MODE_ADHOC)) {
                    ~                    ^               ~
drivers/net/wireless/intel/ipw2x00/ipw2200.c:5655:28: note: use '=' to
turn this equality comparison into an assignment
                if ((priv->ieee->iw_mode == IW_MODE_ADHOC)) {
                                         ^~
                                         =
1 warning generated.

Link: ClangBuiltLinux#134
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
@nathanchance
Copy link
Member

Patch accepted: https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers-next.git/commit/?id=c15ace868dd16300ec67021903cc354fe0aa0762

@nathanchance nathanchance added [PATCH] Accepted A submitted patch has been accepted upstream and removed [PATCH] Submitted A patch has been submitted for review labels Oct 1, 2018
@nathanchance
Copy link
Member

Merged into mainline: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c15ace868dd16300ec67021903cc354fe0aa0762

@nathanchance nathanchance added [FIXED][LINUX] 4.20 This bug was fixed in Linux 4.20 and removed [PATCH] Accepted A submitted patch has been accepted upstream labels Oct 25, 2018
@tpimh tpimh removed the low priority This bug is not critical and not a priority label Oct 26, 2018
nathanchance pushed a commit that referenced this issue Mar 4, 2020
@kawasaki @snitm
dm zoned: Fix reference counter initial value of chunk works
ee63634 
Dm-zoned initializes reference counters of new chunk works with zero
value and refcount_inc() is called to increment the counter. However, the
refcount_inc() function handles the addition to zero value as an error
and triggers the warning as follows:

refcount_t: addition on 0; use-after-free.
WARNING: CPU: 7 PID: 1506 at lib/refcount.c:25 refcount_warn_saturate+0x68/0xf0
...
CPU: 7 PID: 1506 Comm: systemd-udevd Not tainted 5.4.0+ #134
...
Call Trace:
 dmz_map+0x2d2/0x350 [dm_zoned]
 __map_bio+0x42/0x1a0
 __split_and_process_non_flush+0x14a/0x1b0
 __split_and_process_bio+0x83/0x240
 ? kmem_cache_alloc+0x165/0x220
 dm_process_bio+0x90/0x230
 ? generic_make_request_checks+0x2e7/0x680
 dm_make_request+0x3e/0xb0
 generic_make_request+0xcf/0x320
 ? memcg_drain_all_list_lrus+0x1c0/0x1c0
 submit_bio+0x3c/0x160
 ? guard_bio_eod+0x2c/0x130
 mpage_readpages+0x182/0x1d0
 ? bdev_evict_inode+0xf0/0xf0
 read_pages+0x6b/0x1b0
 __do_page_cache_readahead+0x1ba/0x1d0
 force_page_cache_readahead+0x93/0x100
 generic_file_read_iter+0x83a/0xe40
 ? __seccomp_filter+0x7b/0x670
 new_sync_read+0x12a/0x1c0
 vfs_read+0x9d/0x150
 ksys_read+0x5f/0xe0
 do_syscall_64+0x5b/0x180
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
...

After this warning, following refcount API calls for the counter all fail
to change the counter value.

Fix this by setting the initial reference counter value not zero but one
for the new chunk works. Instead, do not call refcount_inc() via
dmz_get_chunk_work() for the new chunks works.

The failure was observed with linux version 5.4 with CONFIG_REFCOUNT_FULL
enabled. Refcount rework was merged to linux version 5.5 by the
commit 168829a ("Merge branch 'locking-core-for-linus' of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip"). After this
commit, CONFIG_REFCOUNT_FULL was removed and the failure was observed
regardless of kernel configuration.

Linux version 4.20 merged the commit 092b564 ("dm zoned: target: use
refcount_t for dm zoned reference counters"). Before this commit, dm
zoned used atomic_t APIs which does not check addition to zero, then this
fix is not necessary.

Fixes: 092b564 ("dm zoned: target: use refcount_t for dm zoned reference counters")
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees

@nathanchance nathanchance

Labels
-Wparentheses-equality [BUG] linux A bug that should be fixed in the mainline kernel. [FIXED][LINUX] 4.20 This bug was fixed in Linux 4.20
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
2 participants
@tpimh @nathanchance