kernel/linux.git/include/trace, branch v5.4.26

rcu: Fix data-race due to atomic_t copy-by-value

2020-02-24T07:36:23+00:00

[ Upstream commit 6cf539a87a61a4fbc43f625267dbcbcf283872ed ] This fixes a data-race where `atomic_t dynticks` is copied by value. The copy is performed non-atomically, resulting in a data-race if `dynticks` is updated concurrently. This data-race was found with KCSAN: ================================================================== BUG: KCSAN: data-race in dyntick_save_progress_counter / rcu_irq_enter write to 0xffff989dbdbe98e0 of 4 bytes by task 10 on cpu 3: atomic_add_return include/asm-generic/atomic-instrumented.h:78 [inline] rcu_dynticks_snap kernel/rcu/tree.c:310 [inline] dyntick_save_progress_counter+0x43/0x1b0 kernel/rcu/tree.c:984 force_qs_rnp+0x183/0x200 kernel/rcu/tree.c:2286 rcu_gp_fqs kernel/rcu/tree.c:1601 [inline] rcu_gp_fqs_loop+0x71/0x880 kernel/rcu/tree.c:1653 rcu_gp_kthread+0x22c/0x3b0 kernel/rcu/tree.c:1799 kthread+0x1b5/0x200 kernel/kthread.c:255 read to 0xffff989dbdbe98e0 of 4 bytes by task 154 on cpu 7: rcu_nmi_enter_common kernel/rcu/tree.c:828 [inline] rcu_irq_enter+0xda/0x240 kernel/rcu/tree.c:870 irq_enter+0x5/0x50 kernel/softirq.c:347 Reported by Kernel Concurrency Sanitizer on: CPU: 7 PID: 154 Comm: kworker/7:1H Not tainted 5.3.0+ #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Workqueue: kblockd blk_mq_run_work_fn ================================================================== Signed-off-by: Marco Elver Cc: Paul E. McKenney Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Joel Fernandes Cc: Ingo Molnar Cc: Dmitry Vyukov Cc: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin

memcg: fix a crash in wb_workfn when a device disappears

2020-02-11T12:35:11+00:00

commit 68f23b89067fdf187763e75a56087550624fdbee upstream. Without memcg, there is a one-to-one mapping between the bdi and bdi_writeback structures. In this world, things are fairly straightforward; the first thing bdi_unregister() does is to shutdown the bdi_writeback structure (or wb), and part of that writeback ensures that no other work queued against the wb, and that the wb is fully drained. With memcg, however, there is a one-to-many relationship between the bdi and bdi_writeback structures; that is, there are multiple wb objects which can all point to a single bdi. There is a refcount which prevents the bdi object from being released (and hence, unregistered). So in theory, the bdi_unregister() *should* only get called once its refcount goes to zero (bdi_put will drop the refcount, and when it is zero, release_bdi gets called, which calls bdi_unregister). Unfortunately, del_gendisk() in block/gen_hd.c never got the memo about the Brave New memcg World, and calls bdi_unregister directly. It does this without informing the file system, or the memcg code, or anything else. This causes the root wb associated with the bdi to be unregistered, but none of the memcg-specific wb's are shutdown. So when one of these wb's are woken up to do delayed work, they try to dereference their wb->bdi->dev to fetch the device name, but unfortunately bdi->dev is now NULL, thanks to the bdi_unregister() called by del_gendisk(). As a result, *boom*. Fortunately, it looks like the rest of the writeback path is perfectly happy with bdi->dev and bdi->owner being NULL, so the simplest fix is to create a bdi_dev_name() function which can handle bdi->dev being NULL. This also allows us to bulletproof the writeback tracepoints to prevent them from dereferencing a NULL pointer and crashing the kernel if one is tracing with memcg's enabled, and an iSCSI device dies or a USB storage stick is pulled. The most common way of triggering this will be hotremoval of a device while writeback with memcg enabled is going on. It was triggering several times a day in a heavily loaded production environment. Google Bug Id: 145475544 Link: https://lore.kernel.org/r/20191227194829.150110-1-tytso@mit.edu Link: http://lkml.kernel.org/r/20191228005211.163952-1-tytso@mit.edu Signed-off-by: Theodore Ts'o Cc: Chris Mason Cc: Tejun Heo Cc: Jens Axboe Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

tracing: xen: Ordered comparison of function pointers

2020-01-29T15:45:30+00:00

commit d0695e2351102affd8efae83989056bc4b275917 upstream. Just as commit 0566e40ce7 ("tracing: initcall: Ordered comparison of function pointers"), this patch fixes another remaining one in xen.h found by clang-9. In file included from arch/x86/xen/trace.c:21: In file included from ./include/trace/events/xen.h:475: In file included from ./include/trace/define_trace.h:102: In file included from ./include/trace/trace_events.h:473: ./include/trace/events/xen.h:69:7: warning: ordered comparison of function \ pointers ('xen_mc_callback_fn_t' (aka 'void (*)(void *)') and 'xen_mc_callback_fn_t') [-Wordered-compare-function-pointers] __field(xen_mc_callback_fn_t, fn) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ./include/trace/trace_events.h:421:29: note: expanded from macro '__field' ^ ./include/trace/trace_events.h:407:6: note: expanded from macro '__field_ext' is_signed_type(type), filter_type); \ ^ ./include/linux/trace_events.h:554:44: note: expanded from macro 'is_signed_type' ^ Fixes: c796f213a6934 ("xen/trace: add multicall tracing") Signed-off-by: Changbin Du Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

mm: khugepaged: add trace status description for SCAN_PAGE_HAS_PRIVATE

2020-01-23T07:22:41+00:00

commit 554913f600b45d73de12ad58c1ac7baa0f22a703 upstream. Commit 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") introduced a new khugepaged scan result: SCAN_PAGE_HAS_PRIVATE, but the corresponding description for trace events were not added. Link: http://lkml.kernel.org/r/1574793844-2914-1-git-send-email-yang.shi@linux.alibaba.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Yang Shi Cc: Song Liu Cc: Kirill A. Shutemov Cc: Anshuman Khandual Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

afs: Fix use-after-loss-of-ref

2020-01-17T18:48:41+00:00

commit 40a708bd622b78582ae3d280de29b09b50bd04c0 upstream. afs_lookup() has a tracepoint to indicate the outcome of d_splice_alias(), passing it the inode to retrieve the fid from. However, the function gave up its ref on that inode when it called d_splice_alias(), which may have failed and dropped the inode. Fix this by caching the fid. Fixes: 80548b03991f ("afs: Add more tracepoints") Reported-by: Al Viro Signed-off-by: David Howells Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

xprtrdma: Add unique trace points for posting Local Invalidate WRs

2020-01-17T18:48:38+00:00

commit 4b93dab36f28e673725e5e6123ebfccf7697f96a upstream. When adding frwr_unmap_async way back when, I re-used the existing trace_xprtrdma_post_send() trace point to record the return code of ib_post_send. Unfortunately there are some cases where re-using that trace point causes a crash. Instead, construct a trace point specific to posting Local Invalidate WRs that will always be safe to use in that context, and will act as a trace log eye-catcher for Local Invalidation. Fixes: 847568942f93 ("xprtrdma: Remove fr_state") Fixes: d8099feda483 ("xprtrdma: Reduce context switching due ... ") Signed-off-by: Chuck Lever Tested-by: Bill Baker Signed-off-by: Anna Schumaker Signed-off-by: Greg Kroah-Hartman

tracing: Change offset type to s32 in preempt/irq tracepoints

2020-01-14T19:08:22+00:00

commit bf44f488e168368cae4139b4b33c3d0aaa11679c upstream. Discussion in the below link reported that symbols in modules can appear to be before _stext on ARM architecture, causing wrapping with the offsets of this tracepoint. Change the offset type to s32 to fix this. Link: http://lore.kernel.org/r/20191127154428.191095-1-antonio.borneo@st.com Link: http://lkml.kernel.org/r/20200102194625.226436-1-joel@joelfernandes.org Cc: Bjorn Helgaas Cc: David Sterba Cc: Ingo Molnar Cc: Mike Rapoport Cc: "Rafael J. Wysocki" Cc: Sakari Ailus Cc: Antonio Borneo Cc: stable@vger.kernel.org Fixes: d59158162e032 ("tracing: Add support for preempt and irq enable/disable events") Signed-off-by: Joel Fernandes (Google) Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

block: Fix writeback throttling W=1 compiler warnings

2019-12-31T15:43:47+00:00

[ Upstream commit 1d200e9d6f635ae894993a7d0f1b9e0b6e522e3b ] Fix the following compiler warnings: In file included from ./include/linux/bitmap.h:9, from ./include/linux/cpumask.h:12, from ./arch/x86/include/asm/cpumask.h:5, from ./arch/x86/include/asm/msr.h:11, from ./arch/x86/include/asm/processor.h:21, from ./arch/x86/include/asm/cpufeature.h:5, from ./arch/x86/include/asm/thread_info.h:53, from ./include/linux/thread_info.h:38, from ./arch/x86/include/asm/preempt.h:7, from ./include/linux/preempt.h:78, from ./include/linux/spinlock.h:51, from ./include/linux/mmzone.h:8, from ./include/linux/gfp.h:6, from ./include/linux/mm.h:10, from ./include/linux/bvec.h:13, from ./include/linux/blk_types.h:10, from block/blk-wbt.c:23: In function 'strncpy', inlined from 'perf_trace_wbt_stat' at ./include/trace/events/wbt.h:15:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'perf_trace_wbt_lat' at ./include/trace/events/wbt.h:58:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'perf_trace_wbt_step' at ./include/trace/events/wbt.h:87:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'perf_trace_wbt_timer' at ./include/trace/events/wbt.h:126:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_stat' at ./include/trace/events/wbt.h:15:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_lat' at ./include/trace/events/wbt.h:58:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_timer' at ./include/trace/events/wbt.h:126:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'strncpy', inlined from 'trace_event_raw_event_wbt_step' at ./include/trace/events/wbt.h:87:1: ./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation] return __builtin_strncpy(p, q, size); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: Johannes Thumshirn Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism"; v4.10). Signed-off-by: Bart Van Assche Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

page_pool: do not release pool until inflight == 0.

2019-12-18T15:09:07+00:00

[ Upstream commit c3f812cea0d7006469d1cf33a4a9f0a12bb4b3a3 ] The page pool keeps track of the number of pages in flight, and it isn't safe to remove the pool until all pages are returned. Disallow removing the pool until all pages are back, so the pool is always available for page producers. Make the page pool responsible for its own delayed destruction instead of relying on XDP, so the page pool can be used without the xdp memory model. When all pages are returned, free the pool and notify xdp if the pool is registered with the xdp memory system. Have the callback perform a table walk since some drivers (cpsw) may share the pool among multiple xdp_rxq_info. Note that the increment of pages_state_release_cnt may result in inflight == 0, resulting in the pool being released. Fixes: d956a048cd3f ("xdp: force mem allocator removal and periodic warning") Signed-off-by: Jonathan Lemon Acked-by: Jesper Dangaard Brouer Acked-by: Ilias Apalodimas Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp: remove redundant new line from tcp_event_sk_skb

2019-11-10T03:41:50+00:00

This removes '\n' from trace event class tcp_event_sk_skb to avoid redundant new blank line and make output compact. Fixes: af4325ecc24f ("tcp: expose sk_state in tcp_retransmit_skb tracepoint") Reviewed-by: Eric Dumazet Reviewed-by: Yafang Shao Signed-off-by: Tony Lu Signed-off-by: David S. Miller