- 26 Aug, 2020 35 commits
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Eiichi Tsukata authored
[ Upstream commit 96cf2a2c ] If xfs_sysfs_init is called with parent_kobj == NULL, UBSAN shows the following warning: UBSAN: null-ptr-deref in ./fs/xfs/xfs_sysfs.h:37:23 member access within null pointer of type 'struct xfs_kobj' Call Trace: dump_stack+0x10e/0x195 ubsan_type_mismatch_common+0x241/0x280 __ubsan_handle_type_mismatch_v1+0x32/0x40 init_xfs_fs+0x12b/0x28f do_one_initcall+0xdd/0x1d0 do_initcall_level+0x151/0x1b6 do_initcalls+0x50/0x8f do_basic_setup+0x29/0x2b kernel_init_freeable+0x19f/0x20b kernel_init+0x11/0x1e0 ret_from_fork+0x22/0x30 Fix it by checking parent_kobj before the code accesses its member. Signed-off-by:
Eiichi Tsukata <devel@etsukata.com> Reviewed-by:
Darrick J. Wong <darrick.wong@oracle.com> [darrick: minor whitespace edits] Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Gaurav Singh authored
[ Upstream commit d8300206 ] Haven't reproduced this issue. This PR is does a minor code cleanup. Signed-off-by:
Gaurav Singh <gaurav1086@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Reviewed-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Mao Wenan authored
[ Upstream commit 481a0d74 ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive virtqueue_get_buf_ctx virtqueue_get_buf_ctx_packed virtqueue_get_buf_ctx_split virtqueue_napi_complete virtqueue_poll //return true virtqueue_napi_schedule //it will reschedule napi to fix this, return false if vq is broken in virtqueue_poll. Signed-off-by:
Mao Wenan <wenan.mao@linux.alibaba.com> Acked-by:
Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/1596354249-96204-1-git-send-email-wenan.mao@linux.alibaba.comSigned-off-by:
Jason Wang <jasowang@redhat.com> Signed-off-by:
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Javed Hasan authored
[ Upstream commit ec007ef4 ] In fc_disc_gpn_id_resp(), skb is supposed to get freed in all cases except for PTR_ERR. However, in some cases it didn't. This fix is to call fc_frame_free(fp) before function returns. Link: https://lore.kernel.org/r/20200729081824.30996-2-jhasan@marvell.comReviewed-by:
Girish Basrur <gbasrur@marvell.com> Reviewed-by:
Santosh Vernekar <svernekar@marvell.com> Reviewed-by:
Saurav Kashyap <skashyap@marvell.com> Reviewed-by:
Shyam Sundar <ssundar@marvell.com> Signed-off-by:
Javed Hasan <jhasan@marvell.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Srinivas Pandruvada authored
[ Upstream commit 4daca379 ] The MSR_TURBO_RATIO_LIMIT can be 0. This is not an error. User can update this MSR via BIOS settings on some systems or can use msr tools to update. Also some systems boot with value = 0. This results in display of cpufreq/cpuinfo_max_freq wrong. This value will be equal to cpufreq/base_frequency, even though turbo is enabled. But platform will still function normally in HWP mode as we get max 1-core frequency from the MSR_HWP_CAPABILITIES. This MSR is already used to calculate cpu->pstate.turbo_freq, which is used for to set policy->cpuinfo.max_freq. But some other places cpu->pstate.turbo_pstate is used. For example to set policy->max. To fix this, also update cpu->pstate.turbo_pstate when updating cpu->pstate.turbo_freq. Signed-off-by:
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by:
Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by:
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Xiubo Li authored
[ Upstream commit a7caa88f ] If the ceph_mdsc_init() fails, it will free the mdsc already. Reported-by: syzbot+b57f46d8d6ea51960b8c@syzkaller.appspotmail.com Signed-off-by:
Xiubo Li <xiubli@redhat.com> Reviewed-by:
Jeff Layton <jlayton@kernel.org> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Signed-off-by:
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Zhe Li authored
[ Upstream commit 798b7347 ] The log of UAF problem is listed below. BUG: KASAN: use-after-free in jffs2_rmdir+0xa4/0x1cc [jffs2] at addr c1f165fc Read of size 4 by task rm/8283 ============================================================================= BUG kmalloc-32 (Tainted: P B O ): kasan: bad access detected ----------------------------------------------------------------------------- INFO: Allocated in 0xbbbbbbbb age=3054364 cpu=0 pid=0 0xb0bba6ef jffs2_write_dirent+0x11c/0x9c8 [jffs2] __slab_alloc.isra.21.constprop.25+0x2c/0x44 __kmalloc+0x1dc/0x370 jffs2_write_dirent+0x11c/0x9c8 [jffs2] jffs2_do_unlink+0x328/0x5fc [jffs2] jffs2_rmdir+0x110/0x1cc [jffs2] vfs_rmdir+0x180/0x268 do_rmdir+0x2cc/0x300 ret_from_syscall+0x0/0x3c INFO: Freed in 0x205b age=3054364 cpu=0 pid=0 0x2e9173 jffs2_add_fd_to_list+0x138/0x1dc [jffs2] jffs2_add_fd_to_list+0x138/0x1dc [jffs2] jffs2_garbage_collect_dirent.isra.3+0x21c/0x288 [jffs2] jffs2_garbage_collect_live+0x16bc/0x1800 [jffs2] jffs2_garbage_collect_pass+0x678/0x11d4 [jffs2] jffs2_garbage_collect_thread+0x1e8/0x3b0 [jffs2] kthread+0x1a8/0x1b0 ret_from_kernel_thread+0x5c/0x64 Call Trace: [c17ddd20] [c02452d4] kasan_report.part.0+0x298/0x72c (unreliable) [c17ddda0] [d2509680] jffs2_rmdir+0xa4/0x1cc [jffs2] [c17dddd0] [c026da04] vfs_rmdir+0x180/0x268 [c17dde00] [c026f4e4] do_rmdir+0x2cc/0x300 [c17ddf40] [c001a658] ret_from_syscall+0x0/0x3c The root cause is that we don't get "jffs2_inode_info.sem" before we scan list "jffs2_inode_info.dents" in function jffs2_rmdir. This patch add codes to get "jffs2_inode_info.sem" before we scan "jffs2_inode_info.dents" to slove the UAF problem. Signed-off-by:
Zhe Li <lizhe67@huawei.com> Reviewed-by:
Hou Tao <houtao1@huawei.com> Signed-off-by:
Richard Weinberger <richard@nod.at> Signed-off-by:
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Darrick J. Wong authored
[ Upstream commit f959b5d0 ] xfs_trans_dqresv is the function that we use to make reservations against resource quotas. Each resource contains two counters: the q_core counter, which tracks resources allocated on disk; and the dquot reservation counter, which tracks how much of that resource has either been allocated or reserved by threads that are working on metadata updates. For disk blocks, we compare the proposed reservation counter against the hard and soft limits to decide if we're going to fail the operation. However, for inodes we inexplicably compare against the q_core counter, not the incore reservation count. Since the q_core counter is always lower than the reservation count and we unlock the dquot between reservation and transaction commit, this means that multiple threads can reserve the last inode count before we hit the hard limit, and when they commit, we'll be well over the hard limit. Fix this by checking against the incore inode reservation counter, since we would appear to maintain that correctly (and that's what we report in GETQUOTA). Signed-off-by:
Allison Collins <allison.henderson@oracle.com> Reviewed-by:
Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Chuck Lever authored
[ Upstream commit 64d26422 ] During a connection tear down, the Receive queue is flushed before the device resources are freed. Typically, all the Receives flush with IB_WR_FLUSH_ERR. However, any pending successful Receives flush with IB_WR_SUCCESS, and the server automatically posts a fresh Receive to replace the completing one. This happens even after the connection has closed and the RQ is drained. Receives that are posted after the RQ is drained appear never to complete, causing a Receive resource leak. The leaked Receive buffer is left DMA-mapped. To prevent these late-posted recv_ctxt's from leaking, block new Receive posting after XPT_CLOSE is set. Signed-off-by:
Chuck Lever <chuck.lever@oracle.com> Signed-off-by:
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Greg Ungerer authored
[ Upstream commit bdee0e79 ] The Cache Control Register (CACR) of the ColdFire V3 has bits that control high level caching functions, and also enable/disable the use of the alternate stack pointer register (the EUSP bit) to provide separate supervisor and user stack pointer registers. The code as it is today will blindly clear the EUSP bit on cache actions like invalidation. So it is broken for this case - and that will result in failed booting (interrupt entry and exit processing will be completely hosed). This only affects ColdFire V3 parts that support the alternate stack register (like the 5329 for example) - generally speaking new parts do, older parts don't. It has no impact on ColdFire V3 parts with the single stack pointer, like the 5307 for example. Fix the cache bit defines used, so they maintain the EUSP bit when carrying out cache actions through the CACR register. Signed-off-by:
Greg Ungerer <gerg@linux-m68k.org> Signed-off-by:
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Xiongfeng Wang authored
[ Upstream commit 4aec14de ] When I cat parameter 'proto' by sysfs, it displays as follows. It's better to add a newline for easy reading. root@syzkaller:~# cat /sys/module/psmouse/parameters/proto autoroot@syzkaller:~# Signed-off-by:
Xiongfeng Wang <wangxiongfeng2@huawei.com> Link: https://lore.kernel.org/r/20200720073846.120724-1-wangxiongfeng2@huawei.comSigned-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
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Evgeny Novikov authored
[ Upstream commit 9c487b0b ] If platform_driver_register() fails within vpss_init() resources are not cleaned up. The patch fixes this issue by introducing the corresponding error handling. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by:
Evgeny Novikov <novikov@ispras.ru> Signed-off-by:
Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by:
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by:
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Huacai Chen authored
[ Upstream commit 22f8d5a1 ] When use goldfish rtc, the "hwclock" command fails with "select() to /dev/rtc to wait for clock tick timed out". This is because "hwclock" need the set_alarm() hook to enable interrupt when alrm->enabled is true. This operation is missing in goldfish rtc (but other rtc drivers, such as cmos rtc, enable interrupt here), so add it. Signed-off-by:
Huacai Chen <chenhc@lemote.com> Signed-off-by:
Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by:
Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/1592654683-31314-1-git-send-email-chenhc@lemote.comSigned-off-by:
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Chuhong Yuan authored
[ Upstream commit fc045645 ] budget_register() has no error handling after its failure. Add the missed undo functions for error handling to fix it. Signed-off-by:
Chuhong Yuan <hslester96@gmail.com> Signed-off-by:
Sean Young <sean@mess.org> Signed-off-by:
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Bodo Stroesser authored
[ Upstream commit 3145550a ] This patch fixes the following crash (see https://bugzilla.kernel.org/show_bug.cgi?id=208045) Process iscsi_trx (pid: 7496, stack limit = 0x0000000010dd111a) CPU: 0 PID: 7496 Comm: iscsi_trx Not tainted 4.19.118-0419118-generic #202004230533 Hardware name: Greatwall QingTian DF720/F601, BIOS 601FBE20 Sep 26 2019 pstate: 80400005 (Nzcv daif +PAN -UAO) pc : flush_dcache_page+0x18/0x40 lr : is_ring_space_avail+0x68/0x2f8 [target_core_user] sp : ffff000015123a80 x29: ffff000015123a80 x28: 0000000000000000 x27: 0000000000001000 x26: ffff000023ea5000 x25: ffffcfa25bbe08b8 x24: 0000000000000078 x23: ffff7e0000000000 x22: ffff000023ea5001 x21: ffffcfa24b79c000 x20: 0000000000000fff x19: ffff7e00008fa940 x18: 0000000000000000 x17: 0000000000000000 x16: ffff2d047e709138 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: ffff2d047fbd0a40 x11: 0000000000000000 x10: 0000000000000030 x9 : 0000000000000000 x8 : ffffc9a254820a00 x7 : 00000000000013b0 x6 : 000000000000003f x5 : 0000000000000040 x4 : ffffcfa25bbe08e8 x3 : 0000000000001000 x2 : 0000000000000078 x1 : ffffcfa25bbe08b8 x0 : ffff2d040bc88a18 Call trace: flush_dcache_page+0x18/0x40 is_ring_space_avail+0x68/0x2f8 [target_core_user] queue_cmd_ring+0x1f8/0x680 [target_core_user] tcmu_queue_cmd+0xe4/0x158 [target_core_user] __target_execute_cmd+0x30/0xf0 [target_core_mod] target_execute_cmd+0x294/0x390 [target_core_mod] transport_generic_new_cmd+0x1e8/0x358 [target_core_mod] transport_handle_cdb_direct+0x50/0xb0 [target_core_mod] iscsit_execute_cmd+0x2b4/0x350 [iscsi_target_mod] iscsit_sequence_cmd+0xd8/0x1d8 [iscsi_target_mod] iscsit_process_scsi_cmd+0xac/0xf8 [iscsi_target_mod] iscsit_get_rx_pdu+0x404/0xd00 [iscsi_target_mod] iscsi_target_rx_thread+0xb8/0x130 [iscsi_target_mod] kthread+0x130/0x138 ret_from_fork+0x10/0x18 Code: f9000bf3 aa0003f3 aa1e03e0 d503201f (f9400260) ---[ end trace 1e451c73f4266776 ]--- The solution is based on patch: "scsi: target: tcmu: Optimize use of flush_dcache_page" which restricts the use of tcmu_flush_dcache_range() to addresses from vmalloc'ed areas only. This patch now replaces the virt_to_page() call in tcmu_flush_dcache_range() - which is wrong for vmalloced addrs - by vmalloc_to_page(). The patch was tested on ARM with kernel 4.19.118 and 5.7.2 Link: https://lore.kernel.org/r/20200618131632.32748-3-bstroesser@ts.fujitsu.comTested-by:
JiangYu <lnsyyj@hotmail.com> Tested-by:
Daniel Meyerholt <dxm523@gmail.com> Acked-by:
Mike Christie <michael.christie@oracle.com> Signed-off-by:
Bodo Stroesser <bstroesser@ts.fujitsu.com> Signed-off-by:
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Stanley Chu authored
[ Upstream commit c0a18ee0 ] It is confirmed that Micron device needs DELAY_BEFORE_LPM quirk to have a delay before VCC is powered off. Sdd Micron vendor ID and this quirk for Micron devices. Link: https://lore.kernel.org/r/20200612012625.6615-2-stanley.chu@mediatek.comReviewed-by:
Bean Huo <beanhuo@micron.com> Reviewed-by:
Alim Akhtar <alim.akhtar@samsung.com> Signed-off-by:
Stanley Chu <stanley.chu@mediatek.com> Signed-off-by:
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Lukas Wunner authored
[ Upstream commit ddf75be4 ] CONFIG_OF_DYNAMIC and CONFIG_ACPI allow adding SPI devices at runtime using a DeviceTree overlay or DSDT patch. CONFIG_SPI_SLAVE allows the same via sysfs. But there are no precautions to prevent adding a device below a controller that's being removed. Such a device is unusable and may not even be able to unbind cleanly as it becomes inaccessible once the controller has been torn down. E.g. it is then impossible to quiesce the device's interrupt. of_spi_notify() and acpi_spi_notify() do hold a ref on the controller, but otherwise run lockless against spi_unregister_controller(). Fix by holding the spi_add_lock in spi_unregister_controller() and bailing out of spi_add_device() if the controller has been unregistered concurrently. Fixes: ce79d54a ("spi/of: Add OF notifier handler") Signed-off-by:
Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v3.19+ Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Octavian Purdila <octavian.purdila@intel.com> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Link: https://lore.kernel.org/r/a8c3205088a969dc8410eec1eba9aface60f36af.1596451035.git.lukas@wunner.deSigned-off-by:
Mark Brown <broonie@kernel.org> Signed-off-by:
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Liang Chen authored
commit 26c7295b upstream. when we create a kthread with ktrhead_create_on_cpu(),the child thread entry is ktread.c:ktrhead() which will be preempted by the parent after call complete(done) while schedule() is not called yet,then the parent will call wait_task_inactive(child) but the child is still on the runqueue, so the parent will schedule_hrtimeout() for 1 jiffy,it will waste a lot of time,especially on startup. parent child ktrhead_create_on_cpu() wait_fo_completion(&done) -----> ktread.c:ktrhead() |----- complete(done);--wakeup and preempted by parent kthread_bind() <------------| |-> schedule();--dequeue here wait_task_inactive(child) | schedule_hrtimeout(1 jiffy) -| So we hope the child just wakeup parent but not preempted by parent, and the child is going to call schedule() soon,then the parent will not call schedule_hrtimeout(1 jiffy) as the child is already dequeue. The same issue for ktrhead_park()&&kthread_parkme(). This patch can save 120ms on rk312x startup with CONFIG_HZ=300. Signed-off-by:
Liang Chen <cl@rock-chips.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Link: https://lkml.kernel.org/r/20200306070133.18335-2-cl@rock-chips.comSigned-off-by:
Chanho Park <chanho61.park@samsung.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Krunoslav Kovac authored
commit d2e59d0f upstream. [Why&How] pow(a,x) is implemented as exp(x*log(a)). log(0) will crash. So return 0^x = 0, unless x=0, convention seems to be 0^0 = 1. Cc: stable@vger.kernel.org Signed-off-by:
Krunoslav Kovac <Krunoslav.Kovac@amd.com> Reviewed-by:
Anthony Koo <Anthony.Koo@amd.com> Acked-by:
Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Signed-off-by:
Alex Deucher <alexander.deucher@amd.com> Signed-off-by:
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Steffen Maier authored
commit 2d9a2c5f upstream. Before v4.15 commit 75492a51 ("s390/scsi: Convert timers to use timer_setup()"), we intentionally only passed zfcp_adapter as context argument to zfcp_fsf_request_timeout_handler(). Since we only trigger adapter recovery, it was unnecessary to sync against races between timeout and (late) completion. Likewise, we only passed zfcp_erp_action as context argument to zfcp_erp_timeout_handler(). Since we only wakeup an ERP action, it was unnecessary to sync against races between timeout and (late) completion. Meanwhile the timeout handlers get timer_list as context argument and do a timer-specific container-of to zfcp_fsf_req which can have been freed. Fix it by making sure that any request timeout handlers, that might just have started before del_timer(), are completed by using del_timer_sync() instead. This ensures the request free happens afterwards. Space time diagram of potential use-after-free: Basic idea is to have 2 or more pending requests whose timeouts run out at almost the same time. req 1 timeout ERP thread req 2 timeout ---------------- ---------------- --------------------------------------- zfcp_fsf_request_timeout_handler fsf_req = from_timer(fsf_req, t, timer) adapter = fsf_req->adapter zfcp_qdio_siosl(adapter) zfcp_erp_adapter_reopen(adapter,...) zfcp_erp_strategy ... zfcp_fsf_req_dismiss_all list_for_each_entry_safe zfcp_fsf_req_complete 1 del_timer 1 zfcp_fsf_req_free 1 zfcp_fsf_req_complete 2 zfcp_fsf_request_timeout_handler del_timer 2 fsf_req = from_timer(fsf_req, t, timer) zfcp_fsf_req_free 2 adapter = fsf_req->adapter ^^^^^^^ already freed Link: https://lore.kernel.org/r/20200813152856.50088-1-maier@linux.ibm.com Fixes: 75492a51 ("s390/scsi: Convert timers to use timer_setup()") Cc: <stable@vger.kernel.org> #4.15+ Suggested-by:
Julian Wiedmann <jwi@linux.ibm.com> Reviewed-by:
Steffen Maier <maier@linux.ibm.com> Signed-off-by:
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zhangyi (F) authored
commit ef3f5830 upstream. jbd2_write_superblock() is under the buffer lock of journal superblock before ending that superblock write, so add a missing unlock_buffer() in in the error path before submitting buffer. Fixes: 742b06b5 ("jbd2: check superblock mapped prior to committing") Signed-off-by:
zhangyi (F) <yi.zhang@huawei.com> Reviewed-by:
Ritesh Harjani <riteshh@linux.ibm.com> Cc: stable@kernel.org Link: https://lore.kernel.org/r/20200620061948.2049579-1-yi.zhang@huawei.comSigned-off-by:
Theodore Ts'o <tytso@mit.edu> Signed-off-by:
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Jan Kara authored
commit 7303cb5b upstream. ext4_search_dir() and ext4_generic_delete_entry() can be called both for standard director blocks and for inline directories stored inside inode or inline xattr space. For the second case we didn't call ext4_check_dir_entry() with proper constraints that could result in accepting corrupted directory entry as well as false positive filesystem errors like: EXT4-fs error (device dm-0): ext4_search_dir:1395: inode #28320400: block 113246792: comm dockerd: bad entry in directory: directory entry too close to block end - offset=0, inode=28320403, rec_len=32, name_len=8, size=4096 Fix the arguments passed to ext4_check_dir_entry(). Fixes: 109ba779 ("ext4: check for directory entries too close to block end") CC: stable@vger.kernel.org Signed-off-by:
Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20200731162135.8080-1-jack@suse.czSigned-off-by:
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Charan Teja Reddy authored
commit 88e8ac11 upstream. The following race is observed with the repeated online, offline and a delay between two successive online of memory blocks of movable zone. P1 P2 Online the first memory block in the movable zone. The pcp struct values are initialized to default values,i.e., pcp->high = 0 & pcp->batch = 1. Allocate the pages from the movable zone. Try to Online the second memory block in the movable zone thus it entered the online_pages() but yet to call zone_pcp_update(). This process is entered into the exit path thus it tries to release the order-0 pages to pcp lists through free_unref_page_commit(). As pcp->high = 0, pcp->count = 1 proceed to call the function free_pcppages_bulk(). Update the pcp values thus the new pcp values are like, say, pcp->high = 378, pcp->batch = 63. Read the pcp's batch value using READ_ONCE() and pass the same to free_pcppages_bulk(), pcp values passed here are, batch = 63, count = 1. Since num of pages in the pcp lists are less than ->batch, then it will stuck in while(list_empty(list)) loop with interrupts disabled thus a core hung. Avoid this by ensuring free_pcppages_bulk() is called with proper count of pcp list pages. The mentioned race is some what easily reproducible without [1] because pcp's are not updated for the first memory block online and thus there is a enough race window for P2 between alloc+free and pcp struct values update through onlining of second memory block. With [1], the race still exists but it is very narrow as we update the pcp struct values for the first memory block online itself. This is not limited to the movable zone, it could also happen in cases with the normal zone (e.g., hotplug to a node that only has DMA memory, or no other memory yet). [1]: https://patchwork.kernel.org/patch/11696389/ Fixes: 5f8dcc21 ("page-allocator: split per-cpu list into one-list-per-migrate-type") Signed-off-by:
Charan Teja Reddy <charante@codeaurora.org> Signed-off-by:
David Hildenbrand <david@redhat.com> Acked-by:
David Rientjes <rientjes@google.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Vinayak Menon <vinmenon@codeaurora.org> Cc: <stable@vger.kernel.org> [2.6+] Link: http://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.orgSigned-off-by:
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Doug Berger authored
commit e08d3fdf upstream. The lowmem_reserve arrays provide a means of applying pressure against allocations from lower zones that were targeted at higher zones. Its values are a function of the number of pages managed by higher zones and are assigned by a call to the setup_per_zone_lowmem_reserve() function. The function is initially called at boot time by the function init_per_zone_wmark_min() and may be called later by accesses of the /proc/sys/vm/lowmem_reserve_ratio sysctl file. The function init_per_zone_wmark_min() was moved up from a module_init to a core_initcall to resolve a sequencing issue with khugepaged. Unfortunately this created a sequencing issue with CMA page accounting. The CMA pages are added to the managed page count of a zone when cma_init_reserved_areas() is called at boot also as a core_initcall. This makes it uncertain whether the CMA pages will be added to the managed page counts of their zones before or after the call to init_per_zone_wmark_min() as it becomes dependent on link order. With the current link order the pages are added to the managed count after the lowmem_reserve arrays are initialized at boot. This means the lowmem_reserve values at boot may be lower than the values used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the ratio values are unchanged. In many cases the difference is not significant, but for example an ARM platform with 1GB of memory and the following memory layout cma: Reserved 256 MiB at 0x0000000030000000 Zone ranges: DMA [mem 0x0000000000000000-0x000000002fffffff] Normal empty HighMem [mem 0x0000000030000000-0x000000003fffffff] would result in 0 lowmem_reserve for the DMA zone. This would allow userspace to deplete the DMA zone easily. Funnily enough $ cat /proc/sys/vm/lowmem_reserve_ratio would fix up the situation because as a side effect it forces setup_per_zone_lowmem_reserve. This commit breaks the link order dependency by invoking init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages have the chance to be properly accounted in their zone(s) and allowing the lowmem_reserve arrays to receive consistent values. Fixes: bc22af74 ("mm: update min_free_kbytes from khugepaged after core initialization") Signed-off-by:
Doug Berger <opendmb@gmail.com> Signed-off-by:
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Wei Yongjun authored
commit 71e84329 upstream. kmemleak report memory leak as follows: unreferenced object 0x607ee4e5f948 (size 8): comm "syz-executor.1", pid 2098, jiffies 4295031601 (age 288.468s) hex dump (first 8 bytes): 00 00 00 00 00 00 00 00 ........ backtrace: relay_open kernel/relay.c:583 [inline] relay_open+0xb6/0x970 kernel/relay.c:563 do_blk_trace_setup+0x4a8/0xb20 kernel/trace/blktrace.c:557 __blk_trace_setup+0xb6/0x150 kernel/trace/blktrace.c:597 blk_trace_ioctl+0x146/0x280 kernel/trace/blktrace.c:738 blkdev_ioctl+0xb2/0x6a0 block/ioctl.c:613 block_ioctl+0xe5/0x120 fs/block_dev.c:1871 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x170/0x1ce fs/ioctl.c:739 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 'chan->buf' is malloced in relay_open() by alloc_percpu() but not free while destroy the relay channel. Fix it by adding free_percpu() before return from relay_destroy_channel(). Fixes: 017c59c0 ("relay: Use per CPU constructs for the relay channel buffer pointers") Reported-by:
Hulk Robot <hulkci@huawei.com> Signed-off-by:
Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Daniel Axtens <dja@axtens.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Akash Goel <akash.goel@intel.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200817122826.48518-1-weiyongjun1@huawei.comSigned-off-by:
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Jann Horn authored
commit bcf85fce upstream. romfs has a superblock field that limits the size of the filesystem; data beyond that limit is never accessed. romfs_dev_read() fetches a caller-supplied number of bytes from the backing device. It returns 0 on success or an error code on failure; therefore, its API can't represent short reads, it's all-or-nothing. However, when romfs_dev_read() detects that the requested operation would cross the filesystem size limit, it currently silently truncates the requested number of bytes. This e.g. means that when the content of a file with size 0x1000 starts one byte before the filesystem size limit, ->readpage() will only fill a single byte of the supplied page while leaving the rest uninitialized, leaking that uninitialized memory to userspace. Fix it by returning an error code instead of truncating the read when the requested read operation would go beyond the end of the filesystem. Fixes: da4458bd ("NOMMU: Make it possible for RomFS to use MTD devices directly") Signed-off-by:
Jann Horn <jannh@google.com> Signed-off-by:
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Josef Bacik authored
[ Upstream commit a47bd78d ] Dave hit this splat during testing btrfs/078: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc6-default+ #1191 Not tainted ------------------------------------------------------ kswapd0/75 is trying to acquire lock: ffffa040e9d04ff8 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] but task is already holding lock: ffffffff8b0c8040 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: __lock_acquire+0x56f/0xaa0 lock_acquire+0xa3/0x440 fs_reclaim_acquire.part.0+0x25/0x30 __kmalloc_track_caller+0x49/0x330 kstrdup+0x2e/0x60 __kernfs_new_node.constprop.0+0x44/0x250 kernfs_new_node+0x25/0x50 kernfs_create_link+0x34/0xa0 sysfs_do_create_link_sd+0x5e/0xd0 btrfs_sysfs_add_devices_dir+0x65/0x100 [btrfs] btrfs_init_new_device+0x44c/0x12b0 [btrfs] btrfs_ioctl+0xc3c/0x25c0 [btrfs] ksys_ioctl+0x68/0xa0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0xe0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __lock_acquire+0x56f/0xaa0 lock_acquire+0xa3/0x440 __mutex_lock+0xa0/0xaf0 btrfs_chunk_alloc+0x137/0x3e0 [btrfs] find_free_extent+0xb44/0xfb0 [btrfs] btrfs_reserve_extent+0x9b/0x180 [btrfs] btrfs_alloc_tree_block+0xc1/0x350 [btrfs] alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs] __btrfs_cow_block+0x143/0x7a0 [btrfs] btrfs_cow_block+0x15f/0x310 [btrfs] push_leaf_right+0x150/0x240 [btrfs] split_leaf+0x3cd/0x6d0 [btrfs] btrfs_search_slot+0xd14/0xf70 [btrfs] btrfs_insert_empty_items+0x64/0xc0 [btrfs] __btrfs_commit_inode_delayed_items+0xb2/0x840 [btrfs] btrfs_async_run_delayed_root+0x10e/0x1d0 [btrfs] btrfs_work_helper+0x2f9/0x650 [btrfs] process_one_work+0x22c/0x600 worker_thread+0x50/0x3b0 kthread+0x137/0x150 ret_from_fork+0x1f/0x30 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: check_prev_add+0x98/0xa20 validate_chain+0xa8c/0x2a00 __lock_acquire+0x56f/0xaa0 lock_acquire+0xa3/0x440 __mutex_lock+0xa0/0xaf0 __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] btrfs_evict_inode+0x3bf/0x560 [btrfs] evict+0xd6/0x1c0 dispose_list+0x48/0x70 prune_icache_sb+0x54/0x80 super_cache_scan+0x121/0x1a0 do_shrink_slab+0x175/0x420 shrink_slab+0xb1/0x2e0 shrink_node+0x192/0x600 balance_pgdat+0x31f/0x750 kswapd+0x206/0x510 kthread+0x137/0x150 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&fs_info->chunk_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/75: #0: ffffffff8b0c8040 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff8b0b50b8 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x54/0x2e0 #2: ffffa040e057c0e8 (&type->s_umount_key#26){++++}-{3:3}, at: trylock_super+0x16/0x50 stack backtrace: CPU: 2 PID: 75 Comm: kswapd0 Not tainted 5.8.0-rc6-default+ #1191 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x16f/0x190 check_prev_add+0x98/0xa20 validate_chain+0xa8c/0x2a00 __lock_acquire+0x56f/0xaa0 lock_acquire+0xa3/0x440 ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] __mutex_lock+0xa0/0xaf0 ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] ? __lock_acquire+0x56f/0xaa0 ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] ? lock_acquire+0xa3/0x440 ? btrfs_evict_inode+0x138/0x560 [btrfs] ? btrfs_evict_inode+0x2fe/0x560 [btrfs] ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs] btrfs_evict_inode+0x3bf/0x560 [btrfs] evict+0xd6/0x1c0 dispose_list+0x48/0x70 prune_icache_sb+0x54/0x80 super_cache_scan+0x121/0x1a0 do_shrink_slab+0x175/0x420 shrink_slab+0xb1/0x2e0 shrink_node+0x192/0x600 balance_pgdat+0x31f/0x750 kswapd+0x206/0x510 ? _raw_spin_unlock_irqrestore+0x3e/0x50 ? finish_wait+0x90/0x90 ? balance_pgdat+0x750/0x750 kthread+0x137/0x150 ? kthread_stop+0x2a0/0x2a0 ret_from_fork+0x1f/0x30 This is because we're holding the chunk_mutex while adding this device and adding its sysfs entries. We actually hold different locks in different places when calling this function, the dev_replace semaphore for instance in dev replace, so instead of moving this call around simply wrap it's operations in NOFS. CC: stable@vger.kernel.org # 4.14+ Reported-by:
David Sterba <dsterba@suse.com> Signed-off-by:
Josef Bacik <josef@toxicpanda.com> Reviewed-by:
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Qu Wenruo authored
[ Upstream commit 1e6e238c ] [BUG] There is a bug report of NULL pointer dereference caused in compress_file_extent(): Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Workqueue: btrfs-delalloc btrfs_delalloc_helper [btrfs] NIP [c008000006dd4d34] compress_file_range.constprop.41+0x75c/0x8a0 [btrfs] LR [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs] Call Trace: [c000000c69093b00] [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs] (unreliable) [c000000c69093bd0] [c008000006dd4ebc] async_cow_start+0x44/0xa0 [btrfs] [c000000c69093c10] [c008000006e14824] normal_work_helper+0xdc/0x598 [btrfs] [c000000c69093c80] [c0000000001608c0] process_one_work+0x2c0/0x5b0 [c000000c69093d10] [c000000000160c38] worker_thread+0x88/0x660 [c000000c69093db0] [c00000000016b55c] kthread+0x1ac/0x1c0 [c000000c69093e20] [c00000000000b660] ret_from_kernel_thread+0x5c/0x7c ---[ end trace f16954aa20d822f6 ]--- [CAUSE] For the following execution route of compress_file_range(), it's possible to hit NULL pointer dereference: compress_file_extent() |- pages = NULL; |- start = async_chunk->start = 0; |- end = async_chunk = 4095; |- nr_pages = 1; |- inode_need_compress() == false; <<< Possible, see later explanation | Now, we have nr_pages = 1, pages = NULL |- cont: |- ret = cow_file_range_inline(); |- if (ret <= 0) { |- for (i = 0; i < nr_pages; i++) { |- WARN_ON(pages[i]->mapping); <<< Crash To enter above call execution branch, we need the following race: Thread 1 (chattr) | Thread 2 (writeback) --------------------------+------------------------------ | btrfs_run_delalloc_range | |- inode_need_compress = true | |- cow_file_range_async() btrfs_ioctl_set_flag() | |- binode_flags |= | BTRFS_INODE_NOCOMPRESS | | compress_file_range() | |- inode_need_compress = false | |- nr_page = 1 while pages = NULL | | Then hit the crash [FIX] This patch will fix it by checking @pages before doing accessing it. This patch is only designed as a hot fix and easy to backport. More elegant fix may make btrfs only check inode_need_compress() once to avoid such race, but that would be another story. Reported-by:
Luciano Chavez <chavez@us.ibm.com> Fixes: 4d3a800e ("btrfs: merge nr_pages input and output parameter in compress_pages") CC: stable@vger.kernel.org # 4.14.x: cecc8d90: btrfs: Move free_pages_out label in inline extent handling branch in compress_file_range CC: stable@vger.kernel.org # 4.14+ Signed-off-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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Nikolay Borisov authored
[ Upstream commit cecc8d90 ] This label is only executed if compress_file_range fails to create an inline extent. So move its code in the semantically related inline extent handling branch. No functional changes. Signed-off-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Josef Bacik authored
[ Upstream commit 3ef3959b ] Chris Murphy reported a problem where rpm ostree will bind mount a bunch of things for whatever voodoo it's doing. But when it does this /proc/mounts shows something like /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0 /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo/bar 0 0 Despite subvolid=256 being subvol=/foo. This is because we're just spitting out the dentry of the mount point, which in the case of bind mounts is the source path for the mountpoint. Instead we should spit out the path to the actual subvol. Fix this by looking up the name for the subvolid we have mounted. With this fix the same test looks like this /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0 /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo 0 0 Reported-by:
Chris Murphy <chris@colorremedies.com> CC: stable@vger.kernel.org # 4.4+ Signed-off-by:
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Marcos Paulo de Souza authored
[ Upstream commit c0c907a4 ] The functions will be used outside of export.c and super.c to allow resolving subvolume name from a given id, eg. for subvolume deletion by id ioctl. Signed-off-by:
Marcos Paulo de Souza <mpdesouza@suse.com> Reviewed-by:
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Hugh Dickins authored
[ Upstream commit f3f99d63 ] syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in __khugepaged_enter(): yes, when one thread is about to dump core, has set core_state, and is waiting for others, another might do something calling __khugepaged_enter(), which now crashes because I lumped the core_state test (known as "mmget_still_valid") into khugepaged_test_exit(). I still think it's best to lump them together, so just in this exceptional case, check mm->mm_users directly instead of khugepaged_test_exit(). Fixes: bbe98f9c ("khugepaged: khugepaged_test_exit() check mmget_still_valid()") Reported-by:
syzbot <syzkaller@googlegroups.com> Signed-off-by:
Hugh Dickins <hughd@google.com> Signed-off-by:
Yang Shi <shy828301@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Song Liu <songliubraving@fb.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Eric Dumazet <edumazet@google.com> Cc: <stable@vger.kernel.org> [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvilsSigned-off-by:
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Hugh Dickins authored
[ Upstream commit bbe98f9c ] Move collapse_huge_page()'s mmget_still_valid() check into khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP only, and earned its mmget_still_valid() check because it inserts a huge pmd entry in place of the page table's pmd entry; whereas collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp() merely clears the page table's pmd entry. But core dumping without mmap lock must have been as open to mistaking a racily cleared pmd entry for a page table at physical page 0, as exit_mmap() was. And we certainly have no interest in mapping as a THP once dumping core. Fixes: 59ea6d06 ("coredump: fix race condition between collapse_huge_page() and core dumping") Signed-off-by:
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Masami Hiramatsu authored
[ Upstream commit 12d572e7 ] Fix the memory leakage in debuginfo__find_trace_events() when the probe point is not found in the debuginfo. If there is no probe point found in the debuginfo, debuginfo__find_probes() will NOT return -ENOENT, but 0. Thus the caller of debuginfo__find_probes() must check the tf.ntevs and release the allocated memory for the array of struct probe_trace_event. The current code releases the memory only if the debuginfo__find_probes() hits an error but not checks tf.ntevs. In the result, the memory allocated on *tevs are not released if tf.ntevs == 0. This fixes the memory leakage by checking tf.ntevs == 0 in addition to ret < 0. Fixes: ff741783 ("perf probe: Introduce debuginfo to encapsulate dwarf information") Signed-off-by:
Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by:
Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/159438668346.62703.10887420400718492503.stgit@devnote2Signed-off-by:
Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by:
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Chris Wilson authored
[ Upstream commit 119c53d2 ] drm_gem_dumb_map_offset() now exists and does everything vgem_gem_dump_map does and *ought* to do. In particular, vgem_gem_dumb_map() was trying to reject mmapping an imported dmabuf by checking the existence of obj->filp. Unfortunately, we always allocated an obj->filp, even if unused for an imported dmabuf. Instead, the drm_gem_dumb_map_offset(), since commit 90378e58 ("drm/gem: drm_gem_dumb_map_offset(): reject dma-buf"), uses the obj->import_attach to reject such invalid mmaps. This prevents vgem from allowing userspace mmapping the dumb handle and attempting to incorrectly fault in remote pages belonging to another device, where there may not even be a struct page. v2: Use the default drm_gem_dumb_map_offset() callback Fixes: af33a919 ("drm/vgem: Enable dmabuf import interfaces") Signed-off-by:
Daniel Vetter <daniel.vetter@ffwll.ch> Cc: <stable@vger.kernel.org> # v4.13+ Link: https://patchwork.freedesktop.org/patch/msgid/20200708154911.21236-1-chris@chris-wilson.co.ukSigned-off-by:
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- 21 Aug, 2020 5 commits
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Greg Kroah-Hartman authored
Tested-by:
Guenter Roeck <linux@roeck-us.net> Tested-by:
Shuah Khan <skhan@linuxfoundation.org> Signed-off-by:
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Sandeep Raghuraman authored
commit f8781228 upstream. Reproducing bug report here: After hibernating and resuming, DPM is not enabled. This remains the case even if you test hibernate using the steps here: https://www.kernel.org/doc/html/latest/power/basic-pm-debugging.html I debugged the problem, and figured out that in the file hardwaremanager.c, in the function, phm_enable_dynamic_state_management(), the check 'if (!hwmgr->pp_one_vf && smum_is_dpm_running(hwmgr) && !amdgpu_passthrough(adev) && adev->in_suspend)' returns true for the hibernate case, and false for the suspend case. This means that for the hibernate case, the AMDGPU driver doesn't enable DPM (even though it should) and simply returns from that function. In the suspend case, it goes ahead and enables DPM, even though it doesn't need to. I debugged further, and found out that in the case of suspend, for the CIK/Hawaii GPUs, smum_is_dpm_running(hwmgr) returns false, while in the case of hibernate, smum_is_dpm_running(hwmgr) returns true. For CIK, the ci_is_dpm_running() function calls the ci_is_smc_ram_running() function, which is ultimately used to determine if DPM is currently enabled or not, and this seems to provide the wrong answer. I've changed the ci_is_dpm_running() function to instead use the same method that some other AMD GPU chips do (e.g Fiji), which seems to read the voltage controller. I've tested on my R9 390 and it seems to work correctly for both suspend and hibernate use cases, and has been stable so far. Bug: https://bugzilla.kernel.org/show_bug.cgi?id=208839Signed-off-by:
Sandeep Raghuraman <sandy.8925@gmail.com> Signed-off-by:
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Marius Iacob authored
commit b5ac98cb upstream. Signed-off-by:
Marius Iacob <themariusus@gmail.com> Cc: stable@vger.kernel.org Signed-off-by:
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Tomasz Maciej Nowak authored
commit 5253cb8c upstream. The maker of this board and its variants, stores MAC address in U-Boot environment. Add alias for bootloader to recognise, to which ethernet node inject the factory MAC address. Signed-off-by:
Tomasz Maciej Nowak <tmn505@gmail.com> Signed-off-by:
Gregory CLEMENT <gregory.clement@bootlin.com> [pali: Backported to 5.4 and older versions] Signed-off-by:
Pali Rohár <pali@kernel.org> Signed-off-by:
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Hugh Dickins authored
commit 18e77600 upstream. Only once have I seen this scenario (and forgot even to notice what forced the eventual crash): a sequence of "BUG: Bad page map" alerts from vm_normal_page(), from zap_pte_range() servicing exit_mmap(); pmd:00000000, pte values corresponding to data in physical page 0. The pte mappings being zapped in this case were supposed to be from a huge page of ext4 text (but could as well have been shmem): my belief is that it was racing with collapse_file()'s retract_page_tables(), found *pmd pointing to a page table, locked it, but *pmd had become 0 by the time start_pte was decided. In most cases, that possibility is excluded by holding mmap lock; but exit_mmap() proceeds without mmap lock. Most of what's run by khugepaged checks khugepaged_test_exit() after acquiring mmap lock: khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so, for example. But retract_page_tables() did not: fix that. The fix is for retract_page_tables() to check khugepaged_test_exit(), after acquiring mmap lock, before doing anything to the page table. Getting the mmap lock serializes with __mmput(), which briefly takes and drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on mm_users makes sure we don't touch the page table once exit_mmap() might reach it, since exit_mmap() will be proceeding without mmap lock, not expecting anyone to be racing with it. Fixes: f3f0e1d2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Song Liu <songliubraving@fb.com> Cc: <stable@vger.kernel.org> [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvilsSigned-off-by:
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