- 21 Nov, 2018 40 commits
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Changwei Ge authored
commit 29aa3016 upstream. Somehow, file system metadata was corrupted, which causes ocfs2_check_dir_entry() to fail in function ocfs2_dir_foreach_blk_el(). According to the original design intention, if above happens we should skip the problematic block and continue to retrieve dir entry. But there is obviouse misuse of brelse around related code. After failure of ocfs2_check_dir_entry(), current code just moves to next position and uses the problematic buffer head again and again during which the problematic buffer head is released for multiple times. I suppose, this a serious issue which is long-lived in ocfs2. This may cause other file systems which is also used in a the same host insane. So we should also consider about bakcporting this patch into linux -stable. Link: http://lkml.kernel.org/r/HK2PR06MB045211675B43EED794E597B6D56E0@HK2PR06MB0452.apcprd06.prod.outlook.comSigned-off-by:
Changwei Ge <ge.changwei@h3c.com> Suggested-by:
Changkuo Shi <shi.changkuo@h3c.com> Reviewed-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Joseph Qi <jiangqi903@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Marc Zyngier authored
commit 832ad0e3 upstream. The Keystone QMSS driver is pretty damaged, in the sense that it does things like this: irq_set_affinity_hint(irq, to_cpumask(&cpu_map)); where cpu_map is a local variable. As we leave the function, this will point to nowhere-land, and things will end-up badly. Instead, let's use a proper cpumask that gets allocated, giving the driver a chance to actually work with things like irqbalance as well as have a hypothetical 64bit future. Cc: stable@vger.kernel.org Acked-by:
Santosh Shilimkar <ssantosh@kernel.org> Signed-off-by:
Marc Zyngier <marc.zyngier@arm.com> Signed-off-by:
Olof Johansson <olof@lixom.net> Signed-off-by:
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Ming Lei authored
commit 8dc765d4 upstream. c2856ae2 ("blk-mq: quiesce queue before freeing queue") has already fixed this race, however the implied synchronize_rcu() in blk_mq_quiesce_queue() can slow down LUN probe a lot, so caused performance regression. Then 1311326c ("blk-mq: avoid to synchronize rcu inside blk_cleanup_queue()") tried to quiesce queue for avoiding unnecessary synchronize_rcu() only when queue initialization is done, because it is usual to see lots of inexistent LUNs which need to be probed. However, turns out it isn't safe to quiesce queue only when queue initialization is done. Because when one SCSI command is completed, the user of sending command can be waken up immediately, then the scsi device may be removed, meantime the run queue in scsi_end_request() is still in-progress, so kernel panic can be caused. In Red Hat QE lab, there are several reports about this kind of kernel panic triggered during kernel booting. This patch tries to address the issue by grabing one queue usage counter during freeing one request and the following run queue. Fixes: 1311326c ("blk-mq: avoid to synchronize rcu inside blk_cleanup_queue()") Cc: Andrew Jones <drjones@redhat.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: linux-scsi@vger.kernel.org Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: James E.J. Bottomley <jejb@linux.vnet.ibm.com> Cc: stable <stable@vger.kernel.org> Cc: jianchao.wang <jianchao.w.wang@oracle.com> Signed-off-by:
Ming Lei <ming.lei@redhat.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
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Quinn Tran authored
commit f635e48e upstream. This patch initializes port speed so that firmware does not set lower operating speed. Setting lower speed in firmware impacts WRITE perfomance. Fixes: 726b8548 ("qla2xxx: Add framework for async fabric discovery") Cc: <stable@vger.kernel.org> Signed-off-by:
Quinn Tran <quinn.tran@cavium.com> Signed-off-by:
Himanshu Madhani <himanshu.madhani@cavium.com> Tested-by:
Laurence Oberman <loberman@redhat.com> Reviewed-by:
Ewan D. Milne <emilne@redhat.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Greg Edwards authored
commit 4542d623 upstream. Commands with protection information included were not truncating the protection iov_iter to the number of protection bytes in the command. This resulted in vhost_scsi mis-calculating the size of the protection SGL in vhost_scsi_calc_sgls(), and including both the protection and data SG entries in the protection SGL. Fixes: 09b13fa8 ("vhost/scsi: Add ANY_LAYOUT support in vhost_scsi_handle_vq") Signed-off-by:
Greg Edwards <gedwards@ddn.com> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Fixes: 09b13fa8 Cc: stable@vger.kernel.org Reviewed-by:
Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
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Gustavo A. R. Silva authored
commit e9a2310f upstream. There is a potential execution path in which function platform_get_resource() returns NULL. If this happens, we will end up having a NULL pointer dereference. Fix this by replacing devm_ioremap with devm_ioremap_resource, which has the NULL check and the memory region request. This code was detected with the help of Coccinelle. Cc: stable@vger.kernel.org Fixes: 97b7129c ("reset: hisilicon: change the definition of hisi_reset_init") Signed-off-by:
Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by:
Stephen Boyd <sboyd@kernel.org> Signed-off-by:
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Mikulas Patocka authored
commit c09bcc91 upstream. Reading the registers without waiting for engine idle returns unpredictable values. These unpredictable values result in display corruption - if atyfb_imageblit reads the content of DP_PIX_WIDTH with the bit DP_HOST_TRIPLE_EN set (from previous invocation), the driver would never ever clear the bit, resulting in display corruption. We don't want to wait for idle because it would degrade performance, so this patch modifies the driver so that it never reads accelerator registers. HOST_CNTL doesn't have to be read, we can just write it with HOST_BYTE_ALIGN because no other part of the driver cares if HOST_BYTE_ALIGN is set. DP_PIX_WIDTH is written in the functions atyfb_copyarea and atyfb_fillrect with the default value and in atyfb_imageblit with the value set according to the source image data. Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> Reviewed-by:
Ville Syrjälä <syrjala@sci.fi> Cc: stable@vger.kernel.org Signed-off-by:
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by:
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Mikulas Patocka authored
commit 3c6c6a78 upstream. The code for manual bit triple is not endian-clean. It builds the variable "hostdword" using byte accesses, therefore we must read the variable with "le32_to_cpu". The patch also enables (hardware or software) bit triple only if the image is monochrome (image->depth). If we want to blit full-color image, we shouldn't use the triple code. Signed-off-by:
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Allen Wild authored
commit fec3624f upstream. Moving the bcm2835 thermal driver to the broadcom directory prevented it from getting enabled for arm64 builds, since the broadcom directory is only available when 32-bit specific ARCH_BCM is set. Fix this by enabling the Broadcom menu for ARCH_BCM or ARCH_BCM2835. Fixes: 6892cf07 ("thermal: bcm2835: move to the broadcom subdirectory") Reviewed-by:
Eric Anholt <eric@anholt.net> Signed-off-by:
Allen Wild <allenwild93@gmail.com> Signed-off-by:
Stefan Wahren <stefan.wahren@i2se.com> Signed-off-by:
Eduardo Valentin <edubezval@gmail.com> Signed-off-by:
Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by:
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Yan, Zheng authored
commit efe32823 upstream. This reverts commit 8b8f53af. splice_dentry() is used by three places. For two places, req->r_dentry is passed to splice_dentry(). In the case of error, req->r_dentry does not get updated. So splice_dentry() should not drop reference. Cc: stable@vger.kernel.org # 4.18+ Signed-off-by:
"Yan, Zheng" <zyan@redhat.com> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Signed-off-by:
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Ilya Dryomov authored
commit 94e6992b upstream. If the read is large enough, we end up spinning in the messenger: libceph: osd0 192.168.122.1:6801 io error libceph: osd0 192.168.122.1:6801 io error libceph: osd0 192.168.122.1:6801 io error This is a receive side limit, so only reads were affected. Cc: stable@vger.kernel.org Signed-off-by:
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Lubomir Rintel authored
commit 786fa584 upstream. When the "xclk" clock was added, it was made mandatory. This broke the driver on an OLPC plaform which doesn't know such clock. Make it optional. Tested on a OLPC XO-1 laptop. Fixes: 0a024d63 ("[media] ov7670: get xclk") Cc: stable@vger.kernel.org # 4.11+ Signed-off-by:
Lubomir Rintel <lkundrak@v3.sk> Signed-off-by:
Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by:
Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by:
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Chris Packham authored
commit 00c5a926 upstream. The correct fieldbit value for the NAND PLL reload trigger is 27. Fixes: commit e120c17a ("clk: mvebu: support for 98DX3236 SoC") Signed-off-by:
Chris Packham <chris.packham@alliedtelesis.co.nz> Signed-off-by:
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Enric Balletbo i Serra authored
commit 665636b2 upstream. Fixes the signedness bug returning '(-22)' on the return type by removing the sanity checker in rockchip_ddrclk_get_parent(). The function should return and unsigned value only and it's safe to remove the sanity checker as the core functions that call get_parent like clk_core_get_parent_by_index already ensures the validity of the clk index returned (index >= core->num_parents). Fixes: a4f182bf ("clk: rockchip: add new clock-type for the ddrclk") Cc: stable@vger.kernel.org Signed-off-by:
Enric Balletbo i Serra <enric.balletbo@collabora.com> Reviewed-by:
Heiko Stuebner <heiko@sntech.de> Signed-off-by:
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Ronald Wahl authored
commit 0f5cb0e6 upstream. Commit a982e45d ("clk: at91: PLL recalc_rate() now using cached MUL and DIV values") removed a check that prevents a division by zero. This now causes a stacktrace when booting the kernel on a at91 platform if the PLL DIV register contains zero. This commit reintroduces this check. Fixes: a982e45d ("clk: at91: PLL recalc_rate() now using cached...") Cc: <stable@vger.kernel.org> Signed-off-by:
Ronald Wahl <rwahl@gmx.de> Acked-by:
Ludovic Desroches <ludovic.desroches@microchip.com> Signed-off-by:
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Krzysztof Kozlowski authored
commit 8985167e upstream. When driver is built as module and DT node contains clocks compatible (e.g. "samsung,s2mps11-clk"), the module will not be autoloaded because module aliases won't match. The modalias from uevent: of:NclocksT<NULL>Csamsung,s2mps11-clk The modalias from driver: platform:s2mps11-clk The devices are instantiated by parent's MFD. However both Device Tree bindings and parent define the compatible for clocks devices. In case of module matching this DT compatible will be used. The issue will not happen if this is a built-in (no need for module matching) or when clocks DT node does not contain compatible (not correct from bindings perspective but working for driver). Note when backporting to stable kernels: adjust the list of device ID entries. Cc: <stable@vger.kernel.org> Fixes: 53c31b34 ("mfd: sec-core: Add of_compatible strings for clock MFD cells") Signed-off-by:
Krzysztof Kozlowski <krzk@kernel.org> Acked-by:
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Richard Weinberger authored
commit 0676b957 upstream. 32bit UML used to define PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP own its own because many years ago not all libcs had these request codes in their UAPI. These days PTRACE_SYSEMU/_SINGLESTEP is well known and part of glibc and our own define becomes problematic. With change c48831d0eebf ("linux/x86: sync sys/ptrace.h with Linux 4.14 [BZ #22433]") glibc turned PTRACE_SYSEMU/_SINGLESTEP into a enum and UML failed to build. Let's drop our define and rely on the fact that every libc has PTRACE_SYSEMU/_SINGLESTEP. Cc: <stable@vger.kernel.org> Cc: Ritesh Raj Sarraf <rrs@researchut.com> Reported-and-tested-by:
Ritesh Raj Sarraf <rrs@researchut.com> Signed-off-by:
Richard Weinberger <richard@nod.at> Signed-off-by:
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Max Filippov authored
commit 40dc948f upstream. The bootloader may pass physical address of the boot parameters structure to the MMUv3 kernel in the register a2. Code in the _SetupMMU block in the arch/xtensa/kernel/head.S is supposed to map that physical address to the virtual address in the configured virtual memory layout. This code haven't been updated when additional 256+256 and 512+512 memory layouts were introduced and it may produce wrong addresses when used with these layouts. Cc: stable@vger.kernel.org Signed-off-by:
Max Filippov <jcmvbkbc@gmail.com> Signed-off-by:
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Max Filippov authored
commit 0773495b upstream. Xtensa ABI requires stack alignment to be at least 16. In noMMU configuration ARCH_SLAB_MINALIGN is used to align stack. Make it at least 16. This fixes the following runtime error in noMMU configuration, caused by interaction between insufficiently aligned stack and alloca function, that results in corruption of on-stack variable in the libc function glob: Caught unhandled exception in 'sh' (pid = 47, pc = 0x02d05d65) - should not happen EXCCAUSE is 15 Cc: stable@vger.kernel.org Signed-off-by:
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Max Filippov authored
commit 4119ba21 upstream. This section collects all source .note.* sections together in the vmlinux image. Without it .note.Linux section may be placed at address 0, while the rest of the kernel is at its normal address, resulting in a huge vmlinux.bin image that may not be linked into the xtensa Image.elf. Cc: stable@vger.kernel.org Signed-off-by:
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Huacai Chen authored
[ Upstream commit 360fe725 ] After commit e509bd7d ("genirq: Allow migration of chained interrupts by installing default action") Loongson-3 fails at here: setup_irq(LOONGSON_HT1_IRQ, &cascade_irqaction); This is because both chained_action and cascade_irqaction don't have IRQF_SHARED flag. This will cause Loongson-3 resume fails because HPET timer interrupt can't be delivered during S3. So we set the irqchip of the chained irq to loongson_irq_chip which doesn't disable the chained irq in CP0.Status. Cc: stable@vger.kernel.org Signed-off-by:
Huacai Chen <chenhc@lemote.com> Signed-off-by:
Paul Burton <paul.burton@mips.com> Patchwork: https://patchwork.linux-mips.org/patch/20434/ Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: Huacai Chen <chenhuacai@gmail.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Huacai Chen authored
[ Upstream commit d06f8a2f ] Masking/unmasking the CPU UART irq in CP0_Status (and redirecting it to other CPUs) may cause interrupts be lost, especially in multi-package machines (Package-0's UART irq cannot be delivered to others). So make mask_loongson_irq() and unmask_loongson_irq() be no-ops. The original problem (UART IRQ may deliver to any core) is also because of masking/unmasking the CPU UART irq in CP0_Status. So it is safe to remove all of the stuff. Signed-off-by:
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Amir Goldstein authored
commit 6cd07870 upstream. linking a non-copied-up file into a non-copied-up parent results in a nested call to mutex_lock_interruptible(&oi->lock). Fix this by copying up target parent before ovl_nlink_start(), same as done in ovl_rename(). ~/unionmount-testsuite$ ./run --ov -s ~/unionmount-testsuite$ ln /mnt/a/foo100 /mnt/a/dir100/ WARNING: possible recursive locking detected -------------------------------------------- ln/1545 is trying to acquire lock: 00000000bcce7c4c (&ovl_i_lock_key[depth]){+.+.}, at: ovl_copy_up_start+0x28/0x7d but task is already holding lock: 0000000026d73d5b (&ovl_i_lock_key[depth]){+.+.}, at: ovl_nlink_start+0x3c/0xc1 [SzM: this seems to be a false positive, but doing the copy-up first is harmless and removes the lockdep splat] Reported-by: syzbot+3ef5c0d1a5cb0b21e6be@syzkaller.appspotmail.com Fixes: 5f8415d6 ("ovl: persistent overlay inode nlink for...") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com> [amir: backport to v4.18] Signed-off-by:
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Miklos Szeredi authored
commit 4c316f2f upstream. Otherwise fuse_dev_do_write() could come in and finish off the request, and the set_bit(FR_SENT, ...) could trigger the WARN_ON(test_bit(FR_SENT, ...)) in request_end(). Signed-off-by:
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Miklos Szeredi authored
commit 908a572b upstream. Using waitqueue_active() is racy. Make sure we issue a wake_up() unconditionally after storing into fc->blocked. After that it's okay to optimize with waitqueue_active() since the first wake up provides the necessary barrier for all waiters, not the just the woken one. Signed-off-by:
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Kirill Tkhai authored
commit d2d2d4fb upstream. After we found req in request_find() and released the lock, everything may happen with the req in parallel: cpu0 cpu1 fuse_dev_do_write() fuse_dev_do_write() req = request_find(fpq, ...) ... spin_unlock(&fpq->lock) ... ... req = request_find(fpq, oh.unique) ... spin_unlock(&fpq->lock) queue_interrupt(&fc->iq, req); ... ... ... ... ... request_end(fc, req); fuse_put_request(fc, req); ... queue_interrupt(&fc->iq, req); Signed-off-by:
Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by:
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Kirill Tkhai authored
commit bc78abbd upstream. We may pick freed req in this way: [cpu0] [cpu1] fuse_dev_do_read() fuse_dev_do_write() list_move_tail(&req->list, ...); ... spin_unlock(&fpq->lock); ... ... request_end(fc, req); ... fuse_put_request(fc, req); if (test_bit(FR_INTERRUPTED, ...)) queue_interrupt(fiq, req); Fix that by keeping req alive until we finish all manipulations. Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com Signed-off-by:
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Quinn Tran authored
commit 5c640053 upstream. This patch fixes issue where driver clears NPort ID map instead of marking handle in use. Once driver clears NPort ID from the database, it can reuse the same NPort ID resulting in a PLOGI failure. [mkp: fixed Himanshu's SoB] Fixes: a084fd68 ("scsi: qla2xxx: Fix re-login for Nport Handle in use") Cc: <stable@vger.kernel.org> Signed-of-by:
Himanshu Madhani <hmadhani@cavium.com> Signed-off-by:
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Quinn Tran authored
commit 1e4ac5d6 upstream. If chip unable to fully initialize, use full shutdown sequence to clear out any stale FW state. Fixes: e315cd28 ("[SCSI] qla2xxx: Code changes for qla data structure refactoring") Cc: stable@vger.kernel.org #4.10 Signed-off-by:
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Quinn Tran authored
commit 7c388f91 upstream. Remove stale debug trace. Fixes: 1eb42f96 ("qla2xxx: Make trace flags more readable") Cc: stable@vger.kernel.org #4.10 Signed-off-by:
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Quinn Tran authored
commit b86ac8fd upstream. This patch improves performance for 16G and above adapter by removing additional call to process_response_queue(). [mkp: typo] Cc: <stable@vger.kernel.org> Signed-off-by:
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Himanshu Madhani authored
commit 4c1458df upstream. Fixes: 6246b8a1 ("[SCSI] qla2xxx: Enhancements to support ISP83xx.") Fixes: 1bb39548 ("qla2xxx: Correct iiDMA-update calling conventions.") Cc: <stable@vger.kernel.org> Signed-off-by:
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Amir Goldstein authored
commit babf4770 upstream. We hit a BUG on kfree of an ERR_PTR()... Reported-by: syzbot+ff03fe05c717b82502d0@syzkaller.appspotmail.com Fixes: 8b88a2e6 ("ovl: verify upper root dir matches lower root dir") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by:
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Young_X authored
commit e4f3aa2e upstream. There is another cast from unsigned long to int which causes a bounds check to fail with specially crafted input. The value is then used as an index in the slot array in cdrom_slot_status(). This issue is similar to CVE-2018-16658 and CVE-2018-10940. Signed-off-by:
Young_X <YangX92@hotmail.com> Signed-off-by:
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Dominique Martinet authored
[ Upstream commit 62e39417 ] p9stat_free is more of a cleanup function than a 'free' function as it only frees the content of the struct; there are chances of use-after-free if it is improperly used (e.g. p9stat_free called twice as it used to be possible to) Clearing dangling pointers makes the function idempotent and safer to use. Link: http://lkml.kernel.org/r/1535410108-20650-2-git-send-email-asmadeus@codewreck.orgSigned-off-by:
Dominique Martinet <dominique.martinet@cea.fr> Reported-by: syzbot+d4252148d198410b864f@syzkaller.appspotmail.com Signed-off-by:
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Dominique Martinet authored
[ Upstream commit b4dc44b3 ] the 9p client code overwrites our glock.client_id pointing to a static buffer by an allocated string holding the network provided value which we do not care about; free and reset the value as appropriate. This is almost identical to the leak in v9fs_file_getlock() fixed by Al Viro in commit ce85dd58 ("9p: we are leaking glock.client_id in v9fs_file_getlock()"), which was returned as an error by a coverity false positive -- while we are here attempt to make the code slightly more robust to future change of the net/9p/client code and hopefully more clear to coverity that there is no problem. Link: http://lkml.kernel.org/r/1536339057-21974-5-git-send-email-asmadeus@codewreck.orgSigned-off-by:
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Alexandru Ardelean authored
[ Upstream commit 4ee03330 ] Fixes commit 17be2a29 ("staging: iio: ad7606: replace range/range_available with corresponding scale"). The AD7606 devices don't have a 2.5V voltage range, they have 5V & 10V voltage range, which is selectable via the `gpio_range` descriptor. The scales also seem to have been miscomputed, because when they were applied to the raw values, the results differ from the expected values. After checking the ADC transfer function in the datasheet, these were re-computed. Signed-off-by:
Alexandru Ardelean <alexandru.ardelean@analog.com> Signed-off-by:
Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by:
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Breno Leitao authored
[ Upstream commit 693b31b2 ] Test tm-tmspr might exit before all threads stop executing, because it just waits for the very last thread to join before proceeding/exiting. This patch makes sure that all threads that were created will join before proceeding/exiting. This patch also guarantees that the amount of threads being created is equal to thread_num. Signed-off-by:
Breno Leitao <leitao@debian.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
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Marco Felsch authored
[ Upstream commit bd24db04 ] The driver ignored the width alignment which exists due to the UYVY colorspace format. Fix the width alignment and make use of the the provided v4l2 helper function to set the width, height and all alignments in one. Fixes: 963ddc63 ("[media] media: tvp5150: Add cropping support") Signed-off-by:
Marco Felsch <m.felsch@pengutronix.de> Signed-off-by:
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Phil Elwell authored
[ Upstream commit 83444987 ] The SC16IS752 is a dual-channel device. The two channels are largely independent, but the IRQ signals are wired together as an open-drain, active low signal which will be driven low while either of the channels requires attention, which can be for significant periods of time until operations complete and the interrupt can be acknowledged. In that respect it is should be treated as a true level-sensitive IRQ. The kernel, however, needs to be able to exit interrupt context in order to use I2C or SPI to access the device registers (which may involve sleeping). Therefore the interrupt needs to be masked out or paused in some way. The usual way to manage sleeping from within an interrupt handler is to use a threaded interrupt handler - a regular interrupt routine does the minimum amount of work needed to triage the interrupt before waking the interrupt service thread. If the threaded IRQ is marked as IRQF_ONESHOT the kernel will automatically mask out the interrupt until the thread runs to completion. The sc16is7xx driver used to use a threaded IRQ, but a patch switched to using a kthread_worker in order to set realtime priorities on the handler thread and for other optimisations. The end result is non-threaded IRQ that schedules some work then returns IRQ_HANDLED, making the kernel think that all IRQ processing has completed. The work-around to prevent a constant stream of interrupts is to mark the interrupt as edge-sensitive rather than level-sensitive, but interpreting an active-low source as a falling-edge source requires care to prevent a total cessation of interrupts. Whereas an edge-triggering source will generate a new edge for every interrupt condition a level-triggering source will keep the signal at the interrupting level until it no longer requires attention; in other words, the host won't see another edge until all interrupt conditions are cleared. It is therefore vital that the interrupt handler does not exit with an outstanding interrupt condition, otherwise the kernel will not receive another interrupt unless some other operation causes the interrupt state on the device to be cleared. The existing sc16is7xx driver has a very simple interrupt "thread" (kthread_work job) that processes interrupts on each channel in turn until there are no more. If both channels are active and the first channel starts interrupting while the handler for the second channel is running then it will not be detected and an IRQ stall ensues. This could be handled easily if there was a shared IRQ status register, or a convenient way to determine if the IRQ had been deasserted for any length of time, but both appear to be lacking. Avoid this problem (or at least make it much less likely to happen) by reducing the granularity of per-channel interrupt processing to one condition per iteration, only exiting the overall loop when both channels are no longer interrupting. Signed-off-by:
Phil Elwell <phil@raspberrypi.org> Signed-off-by:
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