- 20 May, 2020 40 commits
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Jason Gunthorpe authored
commit 01b2bafe upstream. Aside from good practice, this avoids a warning from gcc 10: ./include/linux/kernel.h:997:3: warning: array subscript -31 is outside array bounds of ‘struct list_head[1]’ [-Warray-bounds] 997 | ((type *)(__mptr - offsetof(type, member))); }) | ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./include/linux/list.h:493:2: note: in expansion of macro ‘container_of’ 493 | container_of(ptr, type, member) | ^~~~~~~~~~~~ ./include/linux/pnp.h:275:30: note: in expansion of macro ‘list_entry’ 275 | #define global_to_pnp_dev(n) list_entry(n, struct pnp_dev, global_list) | ^~~~~~~~~~ ./include/linux/pnp.h:281:11: note: in expansion of macro ‘global_to_pnp_dev’ 281 | (dev) != global_to_pnp_dev(&pnp_global); \ | ^~~~~~~~~~~~~~~~~ arch/x86/kernel/rtc.c:189:2: note: in expansion of macro ‘pnp_for_each_dev’ 189 | pnp_for_each_dev(dev) { Because the common code doesn't cast the starting list_head to the containing struct. Signed-off-by:
Jason Gunthorpe <jgg@mellanox.com> [ rjw: Whitespace adjustments ] Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Jack Morgenstein authored
[ Upstream commit 6693ca95 ] In the mlx4_ib_post_send() flow, some functions call ib_get_cached_pkey() without checking its return value. If ib_get_cached_pkey() returns an error code, these functions should return failure. Fixes: 1ffeb2eb ("IB/mlx4: SR-IOV IB context objects and proxy/tunnel SQP support") Fixes: 225c7b1f ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters") Fixes: e622f2f4 ("IB: split struct ib_send_wr") Link: https://lore.kernel.org/r/20200426075921.130074-1-leon@kernel.orgSigned-off-by:
Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by:
Leon Romanovsky <leonro@mellanox.com> Signed-off-by:
Jason Gunthorpe <jgg@mellanox.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Arnd Bergmann authored
[ Upstream commit 2c407aca ] gcc-10 warns around a suspicious access to an empty struct member: net/netfilter/nf_conntrack_core.c: In function '__nf_conntrack_alloc': net/netfilter/nf_conntrack_core.c:1522:9: warning: array subscript 0 is outside the bounds of an interior zero-length array 'u8[0]' {aka 'unsigned char[0]'} [-Wzero-length-bounds] 1522 | memset(&ct->__nfct_init_offset[0], 0, | ^~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from net/netfilter/nf_conntrack_core.c:37: include/net/netfilter/nf_conntrack.h:90:5: note: while referencing '__nfct_init_offset' 90 | u8 __nfct_init_offset[0]; | ^~~~~~~~~~~~~~~~~~ The code is correct but a bit unusual. Rework it slightly in a way that does not trigger the warning, using an empty struct instead of an empty array. There are probably more elegant ways to do this, but this is the smallest change. Fixes: c41884ce ("netfilter: conntrack: avoid zeroing timer") Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Dan Carpenter authored
[ Upstream commit 37e31d2d ] The i40iw_arp_table() function can return -EOVERFLOW if i40iw_alloc_resource() fails so we can't just test for "== -1". Fixes: 4e9042e6 ("i40iw: add hw and utils files") Link: https://lore.kernel.org/r/20200422092211.GA195357@mwandaSigned-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Acked-by:
Shiraz Saleem <shiraz.saleem@intel.com> Signed-off-by:
Jason Gunthorpe <jgg@mellanox.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Grace Kao authored
[ Upstream commit 69388e15 ] According to Braswell NDA Specification Update (#557593), concurrent read accesses may result in returning 0xffffffff and write instructions may be dropped. We have an established format for the commit references, i.e. cdca06e4 ("pinctrl: baytrail: Add missing spinlock usage in byt_gpio_irq_handler") Fixes: 0bd50d71 ("pinctrl: cherryview: prevent concurrent access to GPIO controllers") Signed-off-by:
Grace Kao <grace.kao@intel.com> Reported-by:
Brian Norris <briannorris@chromium.org> Reviewed-by:
Brian Norris <briannorris@chromium.org> Acked-by:
Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Vasily Averin authored
[ Upstream commit 5e698222 ] Commit 89163f93 ("ipc/util.c: sysvipc_find_ipc() should increase position index") is causing this bug (seen on 5.6.8): # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages # ipcmk -Q Message queue id: 0 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x82db8127 0 root 644 0 0 # ipcmk -Q Message queue id: 1 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x82db8127 0 root 644 0 0 0x76d1fb2a 1 root 644 0 0 # ipcrm -q 0 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x76d1fb2a 1 root 644 0 0 0x76d1fb2a 1 root 644 0 0 # ipcmk -Q Message queue id: 2 # ipcrm -q 2 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x76d1fb2a 1 root 644 0 0 0x76d1fb2a 1 root 644 0 0 # ipcmk -Q Message queue id: 3 # ipcrm -q 1 # ipcs -q ------ Message Queues -------- key msqid owner perms used-bytes messages 0x7c982867 3 root 644 0 0 0x7c982867 3 root 644 0 0 0x7c982867 3 root 644 0 0 0x7c982867 3 root 644 0 0 Whenever an IPC item with a low id is deleted, the items with higher ids are duplicated, as if filling a hole. new_pos should jump through hole of unused ids, pos can be updated inside "for" cycle. Fixes: 89163f93 ("ipc/util.c: sysvipc_find_ipc() should increase position index") Reported-by:
Andreas Schwab <schwab@suse.de> Reported-by:
Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
Vasily Averin <vvs@virtuozzo.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Acked-by:
Waiman Long <longman@redhat.com> Cc: NeilBrown <neilb@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Oberparleiter <oberpar@linux.ibm.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/4921fe9b-9385-a2b4-1dc4-1099be6d2e39@virtuozzo.comSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Vasily Averin authored
[ Upstream commit 5b5703db ] v2: removed TODO reminder Signed-off-by:
Vasily Averin <vvs@virtuozzo.com> Link: http://patchwork.freedesktop.org/patch/msgid/a4e0ae09-a73c-1c62-04ef-3f990d41bea9@virtuozzo.comSigned-off-by:
Gerd Hoffmann <kraxel@redhat.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Kai Vehmanen authored
[ Upstream commit ca76282b ] A race exists between build_pcms() and build_controls() phases of codec setup. Build_pcms() sets up notifier for jack events. If a monitor event is received before build_controls() is run, the initial jack state is lost and never reported via mixer controls. The problem can be hit at least with SOF as the controller driver. SOF calls snd_hda_codec_build_controls() in its workqueue-based probe and this can be delayed enough to hit the race condition. Fix the issue by invalidating the per-pin ELD information when build_controls() is called. The existing call to hdmi_present_sense() will update the ELD contents. This ensures initial monitor state is correctly reflected via mixer controls. BugLink: https://github.com/thesofproject/linux/issues/1687Signed-off-by:
Kai Vehmanen <kai.vehmanen@linux.intel.com> Link: https://lore.kernel.org/r/20200428123836.24512-1-kai.vehmanen@linux.intel.comSigned-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Lubomir Rintel authored
[ Upstream commit 0c894463 ] When a channel configuration fails, the status of the channel is set to DEV_ERROR so that an attempt to submit it fails. However, this status sticks until the heat end of the universe, making it impossible to recover from the error. Let's reset it when the channel is released so that further use of the channel with correct configuration is not impacted. Signed-off-by:
Lubomir Rintel <lkundrak@v3.sk> Link: https://lore.kernel.org/r/20200419164912.670973-5-lkundrak@v3.skSigned-off-by:
Vinod Koul <vkoul@kernel.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Madhuparna Bhowmik authored
[ Upstream commit 2e45676a ] pd->dma.dev is read in irq handler pd_irq(). However, it is set to pdev->dev after request_irq(). Therefore, set pd->dma.dev to pdev->dev before request_irq() to avoid data race between pch_dma_probe() and pd_irq(). Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by:
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com> Link: https://lore.kernel.org/r/20200416062335.29223-1-madhuparnabhowmik10@gmail.comSigned-off-by:
Vinod Koul <vkoul@kernel.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Ronnie Sahlberg authored
[ Upstream commit f2caf901 ] There is a race condition with how we send (or supress and don't send) smb echos that will cause the client to incorrectly think the server is unresponsive and thus needs to be reconnected. Summary of the race condition: 1) Daisy chaining scheduling creates a gap. 2) If traffic comes unfortunate shortly after the last echo, the planned echo is suppressed. 3) Due to the gap, the next echo transmission is delayed until after the timeout, which is set hard to twice the echo interval. This is fixed by changing the timeouts from 2 to three times the echo interval. Detailed description of the bug: https://lutz.donnerhacke.de/eng/Blog/Groundhog-Day-with-SMB-remountSigned-off-by:
Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by:
Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by:
Steve French <stfrench@microsoft.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Samuel Cabrero authored
[ Upstream commit 76e75270 ] Some servers seem to accept connections while booting but never send the SMBNegotiate response neither close the connection, causing all processes accessing the share hang on uninterruptible sleep state. This happens when the cifs_demultiplex_thread detects the server is unresponsive so releases the socket and start trying to reconnect. At some point, the faulty server will accept the socket and the TCP status will be set to NeedNegotiate. The first issued command accessing the share will start the negotiation (pid 5828 below), but the response will never arrive so other commands will be blocked waiting on the mutex (pid 55352). This patch checks for unresponsive servers also on the negotiate stage releasing the socket and reconnecting if the response is not received and checking again the tcp state when the mutex is acquired. PID: 55352 TASK: ffff880fd6cc02c0 CPU: 0 COMMAND: "ls" #0 [ffff880fd9add9f0] schedule at ffffffff81467eb9 #1 [ffff880fd9addb38] __mutex_lock_slowpath at ffffffff81468fe0 #2 [ffff880fd9addba8] mutex_lock at ffffffff81468b1a #3 [ffff880fd9addbc0] cifs_reconnect_tcon at ffffffffa042f905 [cifs] #4 [ffff880fd9addc60] smb_init at ffffffffa042faeb [cifs] #5 [ffff880fd9addca0] CIFSSMBQPathInfo at ffffffffa04360b5 [cifs] .... Which is waiting a mutex owned by: PID: 5828 TASK: ffff880fcc55e400 CPU: 0 COMMAND: "xxxx" #0 [ffff880fbfdc19b8] schedule at ffffffff81467eb9 #1 [ffff880fbfdc1b00] wait_for_response at ffffffffa044f96d [cifs] #2 [ffff880fbfdc1b60] SendReceive at ffffffffa04505ce [cifs] #3 [ffff880fbfdc1bb0] CIFSSMBNegotiate at ffffffffa0438d79 [cifs] #4 [ffff880fbfdc1c50] cifs_negotiate_protocol at ffffffffa043b383 [cifs] #5 [ffff880fbfdc1c80] cifs_reconnect_tcon at ffffffffa042f911 [cifs] #6 [ffff880fbfdc1d20] smb_init at ffffffffa042faeb [cifs] #7 [ffff880fbfdc1d60] CIFSSMBQFSInfo at ffffffffa0434eb0 [cifs] .... Signed-off-by:
Samuel Cabrero <scabrero@suse.de> Reviewed-by:
Aurélien Aptel <aaptel@suse.de> Reviewed-by:
Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by:
Steve French <smfrench@gmail.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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wuxu.wu authored
commit 19b61392 upstream. dw_spi_irq() and dw_spi_transfer_one concurrent calls. I find a panic in dw_writer(): txw = *(u8 *)(dws->tx), when dw->tx==null, dw->len==4, and dw->tx_end==1. When tpm driver's message overtime dw_spi_irq() and dw_spi_transfer_one may concurrent visit dw_spi, so I think dw_spi structure lack of protection. Otherwise dw_spi_transfer_one set dw rx/tx buffer and then open irq, store dw rx/tx instructions and other cores handle irq load dw rx/tx instructions may out of order. [ 1025.321302] Call trace: ... [ 1025.321319] __crash_kexec+0x98/0x148 [ 1025.321323] panic+0x17c/0x314 [ 1025.321329] die+0x29c/0x2e8 [ 1025.321334] die_kernel_fault+0x68/0x78 [ 1025.321337] __do_kernel_fault+0x90/0xb0 [ 1025.321346] do_page_fault+0x88/0x500 [ 1025.321347] do_translation_fault+0xa8/0xb8 [ 1025.321349] do_mem_abort+0x68/0x118 [ 1025.321351] el1_da+0x20/0x8c [ 1025.321362] dw_writer+0xc8/0xd0 [ 1025.321364] interrupt_transfer+0x60/0x110 [ 1025.321365] dw_spi_irq+0x48/0x70 ... Signed-off-by:
wuxu.wu <wuxu.wu@huawei.com> Link: https://lore.kernel.org/r/1577849981-31489-1-git-send-email-wuxu.wu@huawei.comSigned-off-by:
Mark Brown <broonie@kernel.org> Signed-off-by:
Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Wu Bo authored
commit 83c6f239 upstream. If the __copy_from_user function failed we need to call sg_remove_request in sg_write. Link: https://lore.kernel.org/r/610618d9-e983-fd56-ed0f-639428343af7@huawei.comAcked-by:
Douglas Gilbert <dgilbert@interlog.com> Signed-off-by:
Wu Bo <wubo40@huawei.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
Sasha Levin <sashal@kernel.org> [groeck: Backport to v5.4.y and older kernels] Signed-off-by:
Guenter Roeck <linux@roeck-us.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Arnd Bergmann authored
[ Upstream commit dc30b405 ] The current gcc-10 snapshot produces a false-positive warning: net/core/drop_monitor.c: In function 'trace_drop_common.constprop': cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=] In file included from net/core/drop_monitor.c:23: include/uapi/linux/net_dropmon.h:36:8: note: at offset 0 to object 'entries' with size 4 declared here 36 | __u32 entries; | ^~~~~~~ I reported this in the gcc bugzilla, but in case it does not get fixed in the release, work around it by using a temporary variable. Fixes: 9a8afc8d ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol") Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94881Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Acked-by:
Neil Horman <nhorman@tuxdriver.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Christophe JAILLET authored
[ Upstream commit ee8d2267 ] Should an irq requested with 'devm_request_irq' be released explicitly, it should be done by 'devm_free_irq()', not 'free_irq()'. Fixes: 6c821bd9 ("net: Add MOXA ART SoCs ethernet driver") Signed-off-by:
Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Christophe JAILLET authored
[ Upstream commit 10e3cc18 ] A call to 'dma_alloc_coherent()' is hidden in 'sonic_alloc_descriptors()', called from 'sonic_probe1()'. This is correctly freed in the remove function, but not in the error handling path of the probe function. Fix it and add the missing 'dma_free_coherent()' call. While at it, rename a label in order to be slightly more informative. Fixes: efcce839 ("[PATCH] macsonic/jazzsonic network drivers update") Signed-off-by:
Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Hugh Dickins authored
[ Upstream commit ea0dfeb4 ] Recent commit 71725ed1 ("mm: huge tmpfs: try to split_huge_page() when punching hole") has allowed syzkaller to probe deeper, uncovering a long-standing lockdep issue between the irq-unsafe shmlock_user_lock, the irq-safe xa_lock on mapping->i_pages, and shmem inode's info->lock which nests inside xa_lock (or tree_lock) since 4.8's shmem_uncharge(). user_shm_lock(), servicing SysV shmctl(SHM_LOCK), wants shmlock_user_lock while its caller shmem_lock() holds info->lock with interrupts disabled; but hugetlbfs_file_setup() calls user_shm_lock() with interrupts enabled, and might be interrupted by a writeback endio wanting xa_lock on i_pages. This may not risk an actual deadlock, since shmem inodes do not take part in writeback accounting, but there are several easy ways to avoid it. Requiring interrupts disabled for shmlock_user_lock would be easy, but it's a high-level global lock for which that seems inappropriate. Instead, recall that the use of info->lock to guard info->flags in shmem_lock() dates from pre-3.1 days, when races with SHMEM_PAGEIN and SHMEM_TRUNCATE could occur: nowadays it serves no purpose, the only flag added or removed is VM_LOCKED itself, and calls to shmem_lock() an inode are already serialized by the caller. Take info->lock out of the chain and the possibility of deadlock or lockdep warning goes away. Fixes: 4595ef88 ("shmem: make shmem_inode_info::lock irq-safe") Reported-by: syzbot+c8a8197c8852f566b9d9@syzkaller.appspotmail.com Reported-by: syzbot+40b71e145e73f78f81ad@syzkaller.appspotmail.com Signed-off-by:
Hugh Dickins <hughd@google.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Acked-by:
Yang Shi <yang.shi@linux.alibaba.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2004161707410.16322@eggly.anvils Link: https://lore.kernel.org/lkml/000000000000e5838c05a3152f53@google.com/ Link: https://lore.kernel.org/lkml/0000000000003712b305a331d3b1@google.com/Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Vladis Dronov authored
commit 75718584 upstream. There is a bug in ptp_clock_unregister(), where ptp_cleanup_pin_groups() first frees ptp->pin_{,dev_}attr, but then posix_clock_unregister() needs them to destroy a related sysfs device. These functions can not be just swapped, as posix_clock_unregister() frees ptp which is needed in the ptp_cleanup_pin_groups(). Fix this by calling ptp_cleanup_pin_groups() in ptp_clock_release(), right before ptp is freed. This makes this patch fix an UAF bug in a patch which fixes an UAF bug. Reported-by:
Antti Laakso <antti.laakso@intel.com> Fixes: a33121e5 ("ptp: fix the race between the release of ptp_clock and cdev") Link: https://lore.kernel.org/netdev/3d2bd09735dbdaf003585ca376b7c1e5b69a19bd.camel@intel.com/Signed-off-by:
Vladis Dronov <vdronov@redhat.com> Acked-by:
Richard Cochran <richardcochran@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Vladis Dronov authored
commit a33121e5 upstream. In a case when a ptp chardev (like /dev/ptp0) is open but an underlying device is removed, closing this file leads to a race. This reproduces easily in a kvm virtual machine: ts# cat openptp0.c int main() { ... fp = fopen("/dev/ptp0", "r"); ... sleep(10); } ts# uname -r 5.5.0-rc3-46cf053e ts# cat /proc/cmdline ... slub_debug=FZP ts# modprobe ptp_kvm ts# ./openptp0 & [1] 670 opened /dev/ptp0, sleeping 10s... ts# rmmod ptp_kvm ts# ls /dev/ptp* ls: cannot access '/dev/ptp*': No such file or directory ts# ...woken up [ 48.010809] general protection fault: 0000 [#1] SMP [ 48.012502] CPU: 6 PID: 658 Comm: openptp0 Not tainted 5.5.0-rc3-46cf053e #25 [ 48.014624] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ... [ 48.016270] RIP: 0010:module_put.part.0+0x7/0x80 [ 48.017939] RSP: 0018:ffffb3850073be00 EFLAGS: 00010202 [ 48.018339] RAX: 000000006b6b6b6b RBX: 6b6b6b6b6b6b6b6b RCX: ffff89a476c00ad0 [ 48.018936] RDX: fffff65a08d3ea08 RSI: 0000000000000247 RDI: 6b6b6b6b6b6b6b6b [ 48.019470] ... ^^^ a slub poison [ 48.023854] Call Trace: [ 48.024050] __fput+0x21f/0x240 [ 48.024288] task_work_run+0x79/0x90 [ 48.024555] do_exit+0x2af/0xab0 [ 48.024799] ? vfs_write+0x16a/0x190 [ 48.025082] do_group_exit+0x35/0x90 [ 48.025387] __x64_sys_exit_group+0xf/0x10 [ 48.025737] do_syscall_64+0x3d/0x130 [ 48.026056] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 48.026479] RIP: 0033:0x7f53b12082f6 [ 48.026792] ... [ 48.030945] Modules linked in: ptp i6300esb watchdog [last unloaded: ptp_kvm] [ 48.045001] Fixing recursive fault but reboot is needed! This happens in: static void __fput(struct file *file) { ... if (file->f_op->release) file->f_op->release(inode, file); <<< cdev is kfree'd here if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL && !(mode & FMODE_PATH))) { cdev_put(inode->i_cdev); <<< cdev fields are accessed here Namely: __fput() posix_clock_release() kref_put(&clk->kref, delete_clock) <<< the last reference delete_clock() delete_ptp_clock() kfree(ptp) <<< cdev is embedded in ptp cdev_put module_put(p->owner) <<< *p is kfree'd, bang! Here cdev is embedded in posix_clock which is embedded in ptp_clock. The race happens because ptp_clock's lifetime is controlled by two refcounts: kref and cdev.kobj in posix_clock. This is wrong. Make ptp_clock's sysfs device a parent of cdev with cdev_device_add() created especially for such cases. This way the parent device with its ptp_clock is not released until all references to the cdev are released. This adds a requirement that an initialized but not exposed struct device should be provided to posix_clock_register() by a caller instead of a simple dev_t. This approach was adopted from the commit 72139dfa ("watchdog: Fix the race between the release of watchdog_core_data and cdev"). See details of the implementation in the commit 233ed09d ("chardev: add helper function to register char devs with a struct device"). Link: https://lore.kernel.org/linux-fsdevel/20191125125342.6189-1-vdronov@redhat.com/T/#uAnalyzed-by:
Stephen Johnston <sjohnsto@redhat.com> Analyzed-by:
Vern Lovejoy <vlovejoy@redhat.com> Signed-off-by:
Vladis Dronov <vdronov@redhat.com> Acked-by:
Richard Cochran <richardcochran@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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YueHaibing authored
commit aea0a897 upstream. Fix smatch warning: drivers/ptp/ptp_clock.c:298 ptp_clock_register() warn: passing zero to 'ERR_PTR' 'err' should be set while device_create_with_groups and pps_register_source fails Fixes: 85a66e55 ("ptp: create "pins" together with the rest of attributes") Signed-off-by:
YueHaibing <yuehaibing@huawei.com> Acked-by:
Richard Cochran <richardcochran@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Logan Gunthorpe authored
commit 233ed09d upstream. Credit for this patch goes is shared with Dan Williams [1]. I've taken things one step further to make the helper function more useful and clean up calling code. There's a common pattern in the kernel whereby a struct cdev is placed in a structure along side a struct device which manages the life-cycle of both. In the naive approach, the reference counting is broken and the struct device can free everything before the chardev code is entirely released. Many developers have solved this problem by linking the internal kobjs in this fashion: cdev.kobj.parent = &parent_dev.kobj; The cdev code explicitly gets and puts a reference to it's kobj parent. So this seems like it was intended to be used this way. Dmitrty Torokhov first put this in place in 2012 with this commit: 2f0157f1 char_dev: pin parent kobject and the first instance of the fix was then done in the input subsystem in the following commit: 4a215aad Input: fix use-after-free introduced with dynamic minor changes Subsequently over the years, however, this issue seems to have tripped up multiple developers independently. For example, see these commits: 0d5b7dae iio: Prevent race between IIO chardev opening and IIO device (by Lars-Peter Clausen in 2013) ba0ef854 tpm: Fix initialization of the cdev (by Jason Gunthorpe in 2015) 5b28dde5 [media] media: fix use-after-free in cdev_put() when app exits after driver unbind (by Shauh Khan in 2016) This technique is similarly done in at least 15 places within the kernel and probably should have been done so in another, at least, 5 places. The kobj line also looks very suspect in that one would not expect drivers to have to mess with kobject internals in this way. Even highly experienced kernel developers can be surprised by this code, as seen in [2]. To help alleviate this situation, and hopefully prevent future wasted effort on this problem, this patch introduces a helper function to register a char device along with its parent struct device. This creates a more regular API for tying a char device to its parent without the developer having to set members in the underlying kobject. This patch introduce cdev_device_add and cdev_device_del which replaces a common pattern including setting the kobj parent, calling cdev_add and then calling device_add. It also introduces cdev_set_parent for the few cases that set the kobject parent without using device_add. [1] https://lkml.org/lkml/2017/2/13/700 [2] https://lkml.org/lkml/2017/2/10/370Signed-off-by:
Logan Gunthorpe <logang@deltatee.com> Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Reviewed-by:
Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by:
Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Dmitry Torokhov authored
commit 85a66e55 upstream. Let's switch to using device_create_with_groups(), which will allow us to create "pins" attribute group together with the rest of ptp device attributes, and before userspace gets notified about ptp device creation. Signed-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> [bwh: Backported to 4.9: adjust context] Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Dmitry Torokhov authored
commit af59e717 upstream. Instead of creating selected attributes after the device is created (and after userspace potentially seen uevent), lets use attribute group is_visible() method to control which attributes are shown. This will allow us to create all attributes (except "pins" group, which will be taken care of later) before userspace gets notified about new ptp class device. Signed-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Dmitry Torokhov authored
commit 882f312d upstream. We do not need explicitly call dev_set_drvdata(), as it is done for us by device_create(). Acked-by:
Richard Cochran <richardcochran@gmail.com> Signed-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Cengiz Can authored
commit 153031a3 upstream. There was a recent change in blktrace.c that added a RCU protection to `q->blk_trace` in order to fix a use-after-free issue during access. However the change missed an edge case that can lead to dereferencing of `bt` pointer even when it's NULL: Coverity static analyzer marked this as a FORWARD_NULL issue with CID 1460458. ``` /kernel/trace/blktrace.c: 1904 in sysfs_blk_trace_attr_store() 1898 ret = 0; 1899 if (bt == NULL) 1900 ret = blk_trace_setup_queue(q, bdev); 1901 1902 if (ret == 0) { 1903 if (attr == &dev_attr_act_mask) >>> CID 1460458: Null pointer dereferences (FORWARD_NULL) >>> Dereferencing null pointer "bt". 1904 bt->act_mask = value; 1905 else if (attr == &dev_attr_pid) 1906 bt->pid = value; 1907 else if (attr == &dev_attr_start_lba) 1908 bt->start_lba = value; 1909 else if (attr == &dev_attr_end_lba) ``` Added a reassignment with RCU annotation to fix the issue. Fixes: c780e86d ("blktrace: Protect q->blk_trace with RCU") Reviewed-by:
Ming Lei <ming.lei@redhat.com> Reviewed-by:
Bob Liu <bob.liu@oracle.com> Reviewed-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
Cengiz Can <cengiz@kernel.wtf> Signed-off-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Jan Kara authored
commit c780e86d upstream. KASAN is reporting that __blk_add_trace() has a use-after-free issue when accessing q->blk_trace. Indeed the switching of block tracing (and thus eventual freeing of q->blk_trace) is completely unsynchronized with the currently running tracing and thus it can happen that the blk_trace structure is being freed just while __blk_add_trace() works on it. Protect accesses to q->blk_trace by RCU during tracing and make sure we wait for the end of RCU grace period when shutting down tracing. Luckily that is rare enough event that we can afford that. Note that postponing the freeing of blk_trace to an RCU callback should better be avoided as it could have unexpected user visible side-effects as debugfs files would be still existing for a short while block tracing has been shut down. Link: https://bugzilla.kernel.org/show_bug.cgi?id=205711 CC: stable@vger.kernel.org Reviewed-by:
Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by:
Ming Lei <ming.lei@redhat.com> Tested-by:
Ming Lei <ming.lei@redhat.com> Reviewed-by:
Bart Van Assche <bvanassche@acm.org> Reported-by:
Tristan Madani <tristmd@gmail.com> Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
Jens Axboe <axboe@kernel.dk> [bwh: Backported to 4.9: adjust context] Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Jens Axboe authored
commit 2967acbb upstream. A previous commit changed the locking around registration/cleanup, but direct callers of blk_trace_remove() were missed. This means that if we hit the error path in setup, we will deadlock on attempting to re-acquire the queue trace mutex. Fixes: 1f2cac10 ("blktrace: fix unlocked access to init/start-stop/teardown") Signed-off-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Jens Axboe authored
commit 1f2cac10 upstream. sg.c calls into the blktrace functions without holding the proper queue mutex for doing setup, start/stop, or teardown. Add internal unlocked variants, and export the ones that do the proper locking. Fixes: 6da127ad ("blktrace: Add blktrace ioctls to SCSI generic devices") Tested-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Waiman Long authored
commit 5acb3cc2 upstream. The lockdep code had reported the following unsafe locking scenario: CPU0 CPU1 ---- ---- lock(s_active#228); lock(&bdev->bd_mutex/1); lock(s_active#228); lock(&bdev->bd_mutex); *** DEADLOCK *** The deadlock may happen when one task (CPU1) is trying to delete a partition in a block device and another task (CPU0) is accessing tracing sysfs file (e.g. /sys/block/dm-1/trace/act_mask) in that partition. The s_active isn't an actual lock. It is a reference count (kn->count) on the sysfs (kernfs) file. Removal of a sysfs file, however, require a wait until all the references are gone. The reference count is treated like a rwsem using lockdep instrumentation code. The fact that a thread is in the sysfs callback method or in the ioctl call means there is a reference to the opended sysfs or device file. That should prevent the underlying block structure from being removed. Instead of using bd_mutex in the block_device structure, a new blk_trace_mutex is now added to the request_queue structure to protect access to the blk_trace structure. Suggested-by:
Christoph Hellwig <hch@infradead.org> Signed-off-by:
Waiman Long <longman@redhat.com> Acked-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Fix typo in patch subject line, and prune a comment detailing how the code used to work. Signed-off-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Sabrina Dubroca authored
commit 6c8991f4 upstream. ipv6_stub uses the ip6_dst_lookup function to allow other modules to perform IPv6 lookups. However, this function skips the XFRM layer entirely. All users of ipv6_stub->ip6_dst_lookup use ip_route_output_flow (via the ip_route_output_key and ip_route_output helpers) for their IPv4 lookups, which calls xfrm_lookup_route(). This patch fixes this inconsistent behavior by switching the stub to ip6_dst_lookup_flow, which also calls xfrm_lookup_route(). This requires some changes in all the callers, as these two functions take different arguments and have different return types. Fixes: 5f81bd2e ("ipv6: export a stub for IPv6 symbols used by vxlan") Reported-by:
Xiumei Mu <xmu@redhat.com> Signed-off-by:
Sabrina Dubroca <sd@queasysnail.net> Signed-off-by:
David S. Miller <davem@davemloft.net> [bwh: Backported to 4.9: - Drop changes in lwt_bpf.c and mlx5 - Initialise "dst" in drivers/infiniband/core/addr.c:addr_resolve() to avoid introducing a spurious "may be used uninitialised" warning - Adjust filename, context, indentation] Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Sabrina Dubroca authored
commit c4e85f73 upstream. This will be used in the conversion of ipv6_stub to ip6_dst_lookup_flow, as some modules currently pass a net argument without a socket to ip6_dst_lookup. This is equivalent to commit 343d60aa ("ipv6: change ipv6_stub_impl.ipv6_dst_lookup to take net argument"). Signed-off-by:
Sabrina Dubroca <sd@queasysnail.net> Signed-off-by:
David S. Miller <davem@davemloft.net> [bwh: Backported to 4.9: adjust context] Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Shijie Luo authored
commit af133ade upstream. When journal size is set too big by "mkfs.ext4 -J size=", or when we mount a crafted image to make journal inode->i_size too big, the loop, "while (i < num)", holds cpu too long. This could cause soft lockup. [ 529.357541] Call trace: [ 529.357551] dump_backtrace+0x0/0x198 [ 529.357555] show_stack+0x24/0x30 [ 529.357562] dump_stack+0xa4/0xcc [ 529.357568] watchdog_timer_fn+0x300/0x3e8 [ 529.357574] __hrtimer_run_queues+0x114/0x358 [ 529.357576] hrtimer_interrupt+0x104/0x2d8 [ 529.357580] arch_timer_handler_virt+0x38/0x58 [ 529.357584] handle_percpu_devid_irq+0x90/0x248 [ 529.357588] generic_handle_irq+0x34/0x50 [ 529.357590] __handle_domain_irq+0x68/0xc0 [ 529.357593] gic_handle_irq+0x6c/0x150 [ 529.357595] el1_irq+0xb8/0x140 [ 529.357599] __ll_sc_atomic_add_return_acquire+0x14/0x20 [ 529.357668] ext4_map_blocks+0x64/0x5c0 [ext4] [ 529.357693] ext4_setup_system_zone+0x330/0x458 [ext4] [ 529.357717] ext4_fill_super+0x2170/0x2ba8 [ext4] [ 529.357722] mount_bdev+0x1a8/0x1e8 [ 529.357746] ext4_mount+0x44/0x58 [ext4] [ 529.357748] mount_fs+0x50/0x170 [ 529.357752] vfs_kern_mount.part.9+0x54/0x188 [ 529.357755] do_mount+0x5ac/0xd78 [ 529.357758] ksys_mount+0x9c/0x118 [ 529.357760] __arm64_sys_mount+0x28/0x38 [ 529.357764] el0_svc_common+0x78/0x130 [ 529.357766] el0_svc_handler+0x38/0x78 [ 529.357769] el0_svc+0x8/0xc [ 541.356516] watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [mount:18674] Link: https://lore.kernel.org/r/20200211011752.29242-1-luoshijie1@huawei.comReviewed-by:
Jan Kara <jack@suse.cz> Signed-off-by:
Shijie Luo <luoshijie1@huawei.com> Signed-off-by:
Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by:
Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Kees Cook authored
commit 7be3cb01 upstream. When brk was moved for binaries without an interpreter, it should have been limited to ET_DYN only. In other words, the special case was an ET_DYN that lacks an INTERP, not just an executable that lacks INTERP. The bug manifested for giant static executables, where the brk would end up in the middle of the text area on 32-bit architectures. Reported-and-tested-by:
Richard Kojedzinszky <richard@kojedz.in> Fixes: bbdc6076 ("binfmt_elf: move brk out of mmap when doing direct loader exec") Cc: stable@vger.kernel.org Signed-off-by:
Kees Cook <keescook@chromium.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Ivan Delalande authored
commit e08df079 upstream. If the trapping instruction contains a ':', for a memory access through segment registers for example, the sed substitution will insert the '*' marker in the middle of the instruction instead of the line address: 2b: 65 48 0f c7 0f cmpxchg16b %gs:*(%rdi) <-- trapping instruction I started to think I had forgotten some quirk of the assembly syntax before noticing that it was actually coming from the script. Fix it to add the address marker at the right place for these instructions: 28: 49 8b 06 mov (%r14),%rax 2b:* 65 48 0f c7 0f cmpxchg16b %gs:(%rdi) <-- trapping instruction 30: 0f 94 c0 sete %al Fixes: 18ff44b1 ("scripts/decodecode: make faulting insn ptr more robust") Signed-off-by:
Ivan Delalande <colona@arista.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Reviewed-by:
Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200419223653.GA31248@visorSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Josh Poimboeuf authored
commit d8dd25a4 upstream. When the current frame address (CFA) is stored on the stack (i.e., cfa->base == CFI_SP_INDIRECT), objtool neglects to adjust the stack offset when there are subsequent pushes or pops. This results in bad ORC data at the end of the ENTER_IRQ_STACK macro, when it puts the previous stack pointer on the stack and does a subsequent push. This fixes the following unwinder warning: WARNING: can't dereference registers at 00000000f0a6bdba for ip interrupt_entry+0x9f/0xa0 Fixes: 627fce14 ("objtool: Add ORC unwind table generation") Reported-by:
Vince Weaver <vincent.weaver@maine.edu> Reported-by:
Dave Jones <dsj@fb.com> Reported-by:
Steven Rostedt <rostedt@goodmis.org> Reported-by:
Vegard Nossum <vegard.nossum@oracle.com> Reported-by:
Joe Mario <jmario@redhat.com> Reviewed-by:
Miroslav Benes <mbenes@suse.cz> Signed-off-by:
Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:
Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/853d5d691b29e250333332f09b8e27410b2d9924.1587808742.git.jpoimboe@redhat.comSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Xiyu Yang authored
commit 6f91a3f7 upstream. batadv_v_ogm_process() invokes batadv_hardif_neigh_get(), which returns a reference of the neighbor object to "hardif_neigh" with increased refcount. When batadv_v_ogm_process() returns, "hardif_neigh" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in one exception handling paths of batadv_v_ogm_process(). When batadv_v_ogm_orig_get() fails to get the orig node and returns NULL, the refcnt increased by batadv_hardif_neigh_get() is not decreased, causing a refcnt leak. Fix this issue by jumping to "out" label when batadv_v_ogm_orig_get() fails to get the orig node. Fixes: 9323158e ("batman-adv: OGMv2 - implement originators logic") Signed-off-by:
Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by:
Xin Tan <tanxin.ctf@gmail.com> Signed-off-by:
Sven Eckelmann <sven@narfation.org> Signed-off-by:
Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Xiyu Yang authored
commit 6107c5da upstream. batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(), which gets a batadv_hard_iface object from net_dev with increased refcnt and its reference is assigned to a local pointer 'hard_iface'. When batadv_store_throughput_override() returns, "hard_iface" becomes invalid, so the refcount should be decreased to keep refcount balanced. The issue happens in one error path of batadv_store_throughput_override(). When batadv_parse_throughput() returns NULL, the refcnt increased by batadv_hardif_get_by_netdev() is not decreased, causing a refcnt leak. Fix this issue by jumping to "out" label when batadv_parse_throughput() returns NULL. Fixes: 0b5ecc68 ("batman-adv: add throughput override attribute to hard_ifaces") Signed-off-by:
Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by:
Xin Tan <tanxin.ctf@gmail.com> Signed-off-by:
Sven Eckelmann <sven@narfation.org> Signed-off-by:
Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Xiyu Yang authored
commit f872de81 upstream. batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(), which gets a batadv_hard_iface object from net_dev with increased refcnt and its reference is assigned to a local pointer 'hard_iface'. When batadv_show_throughput_override() returns, "hard_iface" becomes invalid, so the refcount should be decreased to keep refcount balanced. The issue happens in the normal path of batadv_show_throughput_override(), which forgets to decrease the refcnt increased by batadv_hardif_get_by_netdev() before the function returns, causing a refcnt leak. Fix this issue by calling batadv_hardif_put() before the batadv_show_throughput_override() returns in the normal path. Fixes: 0b5ecc68 ("batman-adv: add throughput override attribute to hard_ifaces") Signed-off-by:
Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by:
Xin Tan <tanxin.ctf@gmail.com> Signed-off-by:
Sven Eckelmann <sven@narfation.org> Signed-off-by:
Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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George Spelvin authored
commit fd0c42c4 upstream. and change to pseudorandom numbers, as this is a traffic dithering operation that doesn't need crypto-grade. The previous code operated in 4 steps: 1. Generate a random byte 0 <= rand_tq <= 255 2. Multiply it by BATADV_TQ_MAX_VALUE - tq 3. Divide by 255 (= BATADV_TQ_MAX_VALUE) 4. Return BATADV_TQ_MAX_VALUE - rand_tq This would apperar to scale (BATADV_TQ_MAX_VALUE - tq) by a random value between 0/255 and 255/255. But! The intermediate value between steps 3 and 4 is stored in a u8 variable. So it's truncated, and most of the time, is less than 255, after which the division produces 0. Specifically, if tq is odd, the product is always even, and can never be 255. If tq is even, there's exactly one random byte value that will produce a product byte of 255. Thus, the return value is 255 (511/512 of the time) or 254 (1/512 of the time). If we assume that the truncation is a bug, and the code is meant to scale the input, a simpler way of looking at it is that it's returning a random value between tq and BATADV_TQ_MAX_VALUE, inclusive. Well, we have an optimized function for doing just that. Fixes: 3c12de9a ("batman-adv: network coding - code and transmit packets if possible") Signed-off-by:
George Spelvin <lkml@sdf.org> Signed-off-by:
Sven Eckelmann <sven@narfation.org> Signed-off-by:
Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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