| Message ID | 20210322160253.4032422-1-arnd@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | treewide: address gcc-11 -Wstringop-overread warnings | expand |
On Mon, Mar 22, 2021 at 05:02:41PM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > gcc-11 introdces a harmless warning for cap_inode_getsecurity: > > security/commoncap.c: In function ‘cap_inode_getsecurity’: > security/commoncap.c:440:33: error: ‘memcpy’ reading 16 bytes from a region of size 0 [-Werror=stringop-overread] > 440 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > The problem here is that tmpbuf is initialized to NULL, so gcc assumes > it is not accessible unless it gets set by vfs_getxattr_alloc(). This is > a legitimate warning as far as I can tell, but the code is correct since > it correctly handles the error when that function fails. > > Add a separate NULL check to tell gcc about it as well. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- Seems reasonable, Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
On Mon, 22 Mar 2021 17:02:38 +0100, Arnd Bergmann wrote: > The coming gcc release introduces a new warning for string operations > reading beyond the end of a fixed-length object. After testing > randconfig kernels for a while, think I have patches for any such > warnings that came up on x86, arm and arm64. > > Most of these warnings are false-positive ones, either gcc warning > about something that is entirely correct, or about something that > looks suspicious but turns out to be correct after all. > > [...] Applied to 5.13/scsi-queue, thanks! [09/11] scsi: lpfc: fix gcc -Wstringop-overread warning https://git.kernel.org/mkp/scsi/c/ada48ba70f6b
From: Arnd Bergmann <arnd@arndb.de> The coming gcc release introduces a new warning for string operations reading beyond the end of a fixed-length object. After testing randconfig kernels for a while, think I have patches for any such warnings that came up on x86, arm and arm64. Most of these warnings are false-positive ones, either gcc warning about something that is entirely correct, or about something that looks suspicious but turns out to be correct after all. The two patches for the i915 driver look like something that might be actual bugs, but I am not sure about those either. We probably want some combination of workaround like the ones I post here and changes to gcc to have fewer false positives in the release. I'm posting the entire set of workaround that give me a cleanly building kernel for reference here. Arnd Arnd Bergmann (11): x86: compressed: avoid gcc-11 -Wstringop-overread warning x86: tboot: avoid Wstringop-overread-warning security: commoncap: fix -Wstringop-overread warning ath11: Wstringop-overread warning qnx: avoid -Wstringop-overread warning cgroup: fix -Wzero-length-bounds warnings ARM: sharpsl_param: work around -Wstringop-overread warning atmel: avoid gcc -Wstringop-overflow warning scsi: lpfc: fix gcc -Wstringop-overread warning drm/i915: avoid stringop-overread warning on pri_latency [RFC] drm/i915/dp: fix array overflow warning arch/arm/common/sharpsl_param.c | 4 ++- arch/x86/boot/compressed/misc.c | 2 -- arch/x86/kernel/tboot.c | 44 +++++++++++++++---------- drivers/gpu/drm/i915/display/intel_dp.c | 2 +- drivers/gpu/drm/i915/i915_drv.h | 6 ++-- drivers/net/wireless/ath/ath11k/mac.c | 2 +- drivers/net/wireless/atmel/atmel.c | 25 ++++++++------ drivers/scsi/lpfc/lpfc_attr.c | 6 ++-- fs/qnx4/dir.c | 11 +++---- kernel/cgroup/cgroup.c | 15 +++++++-- security/commoncap.c | 2 +- 11 files changed, 69 insertions(+), 50 deletions(-) Cc: x86@kernel.org Cc: Ning Sun <ning.sun@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Kalle Valo <kvalo@codeaurora.org> Cc: Simon Kelley <simon@thekelleys.org.uk> Cc: James Smart <james.smart@broadcom.com> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: Anders Larsen <al@alarsen.net> Cc: Tejun Heo <tj@kernel.org> Cc: Serge Hallyn <serge@hallyn.com> Cc: Imre Deak <imre.deak@intel.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: tboot-devel@lists.sourceforge.net Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: ath11k@lists.infradead.org Cc: linux-wireless@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: cgroups@vger.kernel.org Cc: linux-security-module@vger.kernel.org