linux/kernel/events, branch v3.9

events: Protect access via task_subsys_state_check()

2013-04-21T09:21:39Z

The following RCU splat indicates lack of RCU protection: [ 953.267649] =============================== [ 953.267652] [ INFO: suspicious RCU usage. ] [ 953.267657] 3.9.0-0.rc6.git2.4.fc19.ppc64p7 #1 Not tainted [ 953.267661] ------------------------------- [ 953.267664] include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage! [ 953.267669] [ 953.267669] other info that might help us debug this: [ 953.267669] [ 953.267675] [ 953.267675] rcu_scheduler_active = 1, debug_locks = 0 [ 953.267680] 1 lock held by glxgears/1289: [ 953.267683] #0: (&sig->cred_guard_mutex){+.+.+.}, at: [] .prepare_bprm_creds+0x34/0xa0 [ 953.267700] [ 953.267700] stack backtrace: [ 953.267704] Call Trace: [ 953.267709] [c0000001f0d1b6e0] [c000000000016e30] .show_stack+0x130/0x200 (unreliable) [ 953.267717] [c0000001f0d1b7b0] [c0000000001267f8] .lockdep_rcu_suspicious+0x138/0x180 [ 953.267724] [c0000001f0d1b840] [c0000000001d43a4] .perf_event_comm+0x4c4/0x690 [ 953.267731] [c0000001f0d1b950] [c00000000027f6e4] .set_task_comm+0x84/0x1f0 [ 953.267737] [c0000001f0d1b9f0] [c000000000280414] .setup_new_exec+0x94/0x220 [ 953.267744] [c0000001f0d1ba70] [c0000000002f665c] .load_elf_binary+0x58c/0x19b0 ... This commit therefore adds the required RCU read-side critical section to perf_event_comm(). Reported-by: Adam Jackson Signed-off-by: Paul E. McKenney Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: acme@ghostprotocols.net Link: http://lkml.kernel.org/r/20130419190124.GA8638@linux.vnet.ibm.com Signed-off-by: Ingo Molnar Tested-by: Gustavo Luiz Duarte

perf: Treat attr.config as u64 in perf_swevent_init()

2013-04-15T09:42:12Z

Trinity discovered that we fail to check all 64 bits of attr.config passed by user space, resulting to out-of-bounds access of the perf_swevent_enabled array in sw_perf_event_destroy(). Introduced in commit b0a873ebb ("perf: Register PMU implementations"). Signed-off-by: Tommi Rantala Cc: Peter Zijlstra Cc: davej@redhat.com Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Link: http://lkml.kernel.org/r/1365882554-30259-1-git-send-email-tt.rantala@gmail.com Signed-off-by: Ingo Molnar

perf: Fix error return code

2013-04-12T04:33:56Z

Fix to return -ENOMEM in the allocation error case instead of 0 (if pmu_bus_running == 1), as done elsewhere in this function. Signed-off-by: Wei Yongjun Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: acme@ghostprotocols.net Link: http://lkml.kernel.org/r/CAPgLHd8j_fWcgqe%3DKLWjpBj%2B%3Do0Pw6Z-SEq%3DNTPU08c2w1tngQ@mail.gmail.com [ Tweaked the error code setting placement and the changelog. ] Signed-off-by: Ingo Molnar

perf: Fix strncpy() use, always make sure it's NUL terminated

2013-04-08T11:26:55Z

For NUL terminated string, always make sure that there's '\0' at the end. In our case we need a return value, so still use strncpy() and fix up the tail explicitly. (strlcpy() returns the size, not the pointer) Signed-off-by: Chen Gang Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: acme@ghostprotocols.net Link: http://lkml.kernel.org/r/51623E0B.7070101@asianux.com Signed-off-by: Ingo Molnar

perf: Fix ring_buffer perf_output_space() boundary calculation

2013-03-21T11:04:35Z

This patch fixes a flaw in perf_output_space(). In case the size of the space needed is bigger than the actual buffer size, there may be situations where the function would return true (i.e., there is space) when it should not. head > offset due to rounding of the masking logic. The problem can be tested by activating BTS on Intel processors. A BTS record can be as big as 16 pages. The following command fails: $ perf record -m 4 -c 1 -e branches:u my_test_program You will get a buffer corruption with this. Perf report won't be able to parse the perf.data. The fix is to first check that the requested space is smaller than the buffer size. If so, then the masking logic will work fine. If not, then there is no chance the record can be saved and it will be gracefully handled by upper code layers. [ In v2, we also make the logic for the writable more explicit by renaming it to rb->overwrite because it tells whether or not the buffer can overwrite its tail (suggested by PeterZ). ] Signed-off-by: Stephane Eranian Acked-by: Peter Zijlstra Cc: peterz@infradead.org Cc: jolsa@redhat.com Cc: fweisbec@gmail.com Link: http://lkml.kernel.org/r/20130318133327.GA3056@quad Signed-off-by: Ingo Molnar

perf: Generate EXIT event only once per task context

2013-03-18T08:47:33Z

perf_event_task_event() iterates pmu list and generate events for each eligible pmu context. But if task_event has task_ctx like in EXIT it'll generate events even though the pmu doesn't have an eligible one. Fix it by moving the code to proper places. Before this patch: $ perf record -n true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.006 MB perf.data (~248 samples) ] $ perf report -D | tail Aggregated stats: TOTAL events: 73 MMAP events: 67 COMM events: 2 EXIT events: 4 cycles stats: TOTAL events: 73 MMAP events: 67 COMM events: 2 EXIT events: 4 After this patch: $ perf report -D | tail Aggregated stats: TOTAL events: 70 MMAP events: 67 COMM events: 2 EXIT events: 1 cycles stats: TOTAL events: 70 MMAP events: 67 COMM events: 2 EXIT events: 1 Signed-off-by: Namhyung Kim Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1363332433-7637-1-git-send-email-namhyung@kernel.org Signed-off-by: Ingo Molnar

perf: Reset hwc->last_period on sw clock events

2013-03-18T08:15:18Z

When cpu/task clock events are initialized, their sampling frequencies are converted to have a fixed value. However it missed to update the hwc->last_period which was set to 1 for initial sampling frequency calibration. Because this hwc->last_period value is used as a period in perf_swevent_ hrtime(), every recorded sample will have an incorrected period of 1. $ perf record -e task-clock noploop 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.158 MB perf.data (~6919 samples) ] $ perf report -n --show-total-period --stdio # Samples: 4K of event 'task-clock' # Event count (approx.): 4000 # # Overhead Samples Period Command Shared Object Symbol # ........ ............ ............ ....... ............. .................. # 99.95% 3998 3998 noploop noploop [.] main 0.03% 1 1 noploop libc-2.15.so [.] init_cacheinfo 0.03% 1 1 noploop ld-2.15.so [.] open_verify Note that it doesn't affect the non-sampling event so that the perf stat still gets correct value with or without this patch. $ perf stat -e task-clock noploop 1 Performance counter stats for 'noploop 1': 1000.272525 task-clock # 1.000 CPUs utilized 1.000560605 seconds time elapsed Signed-off-by: Namhyung Kim Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1363574507-18808-1-git-send-email-namhyung@kernel.org Signed-off-by: Ingo Molnar

hlist: drop the node parameter from iterators

2013-02-28T03:10:24Z

I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin Acked-by: Paul E. McKenney Signed-off-by: Sasha Levin Cc: Wu Fengguang Cc: Marcelo Tosatti Cc: Gleb Natapov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

events: convert to idr_alloc()

2013-02-28T03:10:19Z

Convert to the much saner new idr interface. Signed-off-by: Tejun Heo Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-02-27T04:16:07Z

Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...