From: Dan Carpenter <error27@gmail.com>
To: Alex Elder <alex.elder@linaro.org>
Cc: elder@linaro.org, kernel-janitors@vger.kernel.org
Subject: Re: [bug report] net: ipa: reduce arguments to ipa_table_init_add()
Date: Fri, 18 Nov 2022 12:50:40 +0300 [thread overview]
Message-ID: <Y3dVcNt32yPgP3EC@kadam> (raw)
In-Reply-To: <Y3W83708rvg1Krvy@kadam>
[-- Attachment #1: Type: text/plain, Size: 1075 bytes --]
On Thu, Nov 17, 2022 at 07:47:27AM +0300, Dan Carpenter wrote:
> Heh. It really feels like this line should have generated a checker
> warning as well. I've created two versions. The first complains when
> ever there is a divide used as a condition:
>
> if (a / b) {
>
> The other complains when it's part of a logical && or ||.
>
> if (a && a / b) {
>
> drivers/net/ipa/ipa_table.c:414 ipa_table_init_add() warn: divide condition: 'hash_mem->size / 8'
> drivers/net/ipa/ipa_table.c:414 ipa_table_init_add() warn: divide condition (logical): 'hash_mem->size / 8'
>
> I'll test them out tonight and see if either gives useful results.
I modified the test to ignore macros. Otherwise we get warnings where
macros are trying to avoid divide by zero bugs. There was no advantage
in treating logicals as special so I dropped that.
The results are kind of mind bending. I think maybe people sometimes
accidentally write "if (a / b) {" meaning does it divide cleanly? When
that should be written as: "if ((a % b) == 0) {".
Anyway, attached.
regards,
dan carpenter
[-- Attachment #2: err-list --]
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drivers/nvdimm/claim.c:287 nsio_rw_bytes() warn: divide condition: 'cleared / 512'
drivers/nvdimm/bus.c:210 nvdimm_account_cleared_poison() warn: divide condition: 'cleared / 512'
drivers/rtc/rtc-m48t59.c:135 m48t59_rtc_set_time() warn: divide condition: 'year / 100'
drivers/gpu/drm/i915/gvt/vgpu.c:124 intel_gvt_init_vgpu_types() warn: divide condition: 'low_avail / conf->low_mm'
drivers/regulator/aat2870-regulator.c:142 aat2870_get_regulator() warn: divide condition: '(id - 1) / 2'
drivers/leds/leds-bcm6328.c:116 bcm6328_led_mode() warn: divide condition: 'shift / 16'
drivers/leds/leds-bcm6328.c:357 bcm6328_led() warn: divide condition: 'shift / 16'
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c:22554 wlc_phy_rssi_cal_nphy_rev3() warn: divide condition: 'result_idx / 2'
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_n.c:22926 wlc_phy_rssi_cal_nphy_rev2() warn: divide condition: 'result_idx / 2'
drivers/net/wireless/broadcom/b43/phy_n.c:2202 b43_nphy_rev3_rssi_cal() warn: divide condition: 'i / 2'
drivers/net/wireless/broadcom/b43/phy_n.c:2403 b43_nphy_rev2_rssi_cal() warn: divide condition: 'i / 2'
drivers/net/wireless/intersil/hostap/hostap_plx.c:232 hfa384x_from_bap() warn: divide condition: 'len / 2'
drivers/net/wireless/intersil/hostap/hostap_plx.c:251 hfa384x_to_bap() warn: divide condition: 'len / 2'
drivers/net/wireless/intersil/hostap/hostap_cs.c:164 hfa384x_from_bap() warn: divide condition: 'len / 2'
drivers/net/wireless/intersil/hostap/hostap_cs.c:183 hfa384x_to_bap() warn: divide condition: 'len / 2'
drivers/net/ethernet/intel/iavf/iavf_txrx.c:300 iavf_clean_tx_irq() warn: divide condition: 'j / 4'
drivers/net/ethernet/intel/i40e/i40e_txrx_common.h:77 i40e_arm_wb() warn: divide condition: 'j / 4'
drivers/net/ethernet/intel/i40e/i40e_txrx_common.h:77 i40e_arm_wb() warn: divide condition: 'j / 4'
drivers/net/ethernet/intel/fm10k/fm10k_netdev.c:759 fm10k_uc_vlan_unsync() warn: divide condition: 'vid / 4096'
drivers/net/ethernet/intel/fm10k/fm10k_netdev.c:779 fm10k_mc_vlan_unsync() warn: divide condition: 'vid / 4096'
drivers/net/ipa/ipa_table.c:414 ipa_table_init_add() warn: divide condition: 'hash_mem->size / 8'
drivers/gpio/gpio-exar.c:52 exar_offset_to_sel_addr() warn: divide condition: 'pin / 8'
drivers/gpio/gpio-exar.c:62 exar_offset_to_lvl_addr() warn: divide condition: 'pin / 8'
drivers/ata/ahci_imx.c:411 __sata_ahci_read_temperature() warn: divide condition: 'm2 / 1000'
fs/hfsplus/bitmap.c:46 hfsplus_block_allocate() warn: divide condition: '(size ^ offset) / (((1) << 12) * 8)'
fs/hfsplus/bitmap.c:88 hfsplus_block_allocate() warn: divide condition: '(size ^ offset) / (((1) << 12) * 8)'
fs/freevxfs/vxfs_bmap.c:62 vxfs_bmap_ext4() warn: divide condition: 'bn / (indsize * indsize * bsize / 4)'
sound/soc/codecs/rt274.c:881 rt274_set_bclk_ratio() warn: divide condition: 'ratio / 50'
next prev parent reply other threads:[~2022-11-18 9:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-15 13:03 [bug report] net: ipa: reduce arguments to ipa_table_init_add() Dan Carpenter
2022-11-15 17:00 ` Alex Elder
2022-11-17 4:47 ` Dan Carpenter
2022-11-18 9:50 ` Dan Carpenter [this message]
2022-11-19 9:21 ` Alex Elder
2022-11-19 10:48 ` Dan Carpenter
2022-11-19 9:04 ` Alex Elder
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