Move SIGTRAP on exec(2) logic from tracehook_report_exec() to
ptrace_event(). This is part of changes to make ptrace_event()
smarter and handle ptrace event related details in one place.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This patch implements ptrace_event_enabled() which tests whether a
given PTRACE_EVENT_* is enabled and use it to simplify ptrace_event()
and tracehook_prepare_clone().
PT_EVENT_FLAG() macro is added which calculates PT_TRACE_* flag from
PTRACE_EVENT_*. This is used to define PT_TRACE_* flags and by
ptrace_event_enabled() to find the matching flag.
This is used to make ptrace_event() and tracehook_prepare_clone()
simpler.
* ptrace_event() callers were responsible for providing mask to test
whether the event was enabled. This patch implements
ptrace_event_enabled() and make ptrace_event() drop @mask and
determine whether the event is enabled from @event. Note that
@event is constant and this conversion doesn't add runtime overhead.
All conversions except tracehook_report_clone_complete() are
trivial. tracehook_report_clone_complete() used to use 0 for @mask
(always enabled) but now tests whether the specified event is
enabled. This doesn't cause any behavior difference as it's
guaranteed that the event specified by @trace is enabled.
* tracehook_prepare_clone() now only determines which event is
applicable and use ptrace_event_enabled() for enable test.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
task_ptrace(task) simply dereferences task->ptrace and isn't even used
consistently only adding confusion. Kill it and directly access
->ptrace instead.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
There are enough instances of this:
iph->frag_off & htons(IP_MF | IP_OFFSET)
that a helper function is probably warranted.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove linux/mm.h inclusion from netdevice.h -- it's unused (I've checked manually).
To prevent mm.h inclusion via other channels also extract "enum dma_data_direction"
definition into separate header. This tiny piece is what gluing netdevice.h with mm.h
via "netdevice.h => dmaengine.h => dma-mapping.h => scatterlist.h => mm.h".
Removal of mm.h from scatterlist.h was tried and was found not feasible
on most archs, so the link was cutoff earlier.
Hope people are OK with tiny include file.
Note, that mm_types.h is still dragged in, but it is a separate story.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Fix decode_secinfo_maxsz
NFSv4.1: Fix an off-by-one error in pnfs_generic_pg_test
NFSv4.1: Fix some issues with pnfs_generic_pg_test
NFSv4.1: file layout must consider pg_bsize for coalescing
pnfs-obj: No longer needed to take an extra ref at add_device
SUNRPC: Ensure the RPC client only quits on fatal signals
NFSv4: Fix a readdir regression
nfs4.1: mark layout as bad on error path in _pnfs_return_layout
nfs4.1: prevent race that allowed use of freed layout in _pnfs_return_layout
NFSv4.1: need to put_layout_hdr on _pnfs_return_layout error path
NFS: (d)printks should use %zd for ssize_t arguments
NFSv4.1: fix break condition in pnfs_find_lseg
nfs4.1: fix several problems with _pnfs_return_layout
NFSv4.1: allow zero fh array in filelayout decode layout
NFSv4.1: allow nfs_fhget to succeed with mounted on fileid
NFSv4.1: Fix a refcounting issue in the pNFS device id cache
NFSv4.1: deprecate headerpadsz in CREATE_SESSION
NFS41: do not update isize if inode needs layoutcommit
NLM: Don't hang forever on NLM unlock requests
NFS: fix umount of pnfs filesystems
Incorrect return type on dcb_setapp() this routine
returns negative error codes. All call sites of
dcb_setapp() assign the return value to an int already
so no need to update drivers.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With multiple APP entries per selector and protocol drivers
or stacks may want to pick a specific value or stripe traffic
across many priorities. Also if an APP entry in use is
deleted the stack/driver may want to choose from the existing
APP entries.
To facilitate this and avoid having duplicate code to walk
the APP ring provide a routine dcb_ieee_getapp_mask() to
return a u8 bitmask of all priorities set for the specified
selector and protocol. This routine and bitmask is a helper
for DCB kernel users.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we allow multiple IEEE App entries we need a way
to remove specific entries. To do this add the ieee_dcb_delapp()
routine.
Additionaly drivers may need to remove the APP entry from
their firmware tables. Add dcb ops routine to handle this.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds a setapp routine for IEEE802.1Qaz encoded APP data types.
The IEEE 802.1Qaz spec encodes the priority bits differently and
allows for multiple APP data entries of the same selector and
protocol. Trying to force these to use the same set routines was
becoming tedious. Furthermore, userspace could probably enforce
the correct semantics, but expecting drivers to do this seems
error prone in the firmware case.
For these reasons add ieee_dcb_setapp() that understands the
IEEE 802.1Qaz encoded form.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that dcbnl is being used in many cases by more
than a single agent it is beneficial to be notified
when some entity either driver or user space has
changed the DCB attributes.
Today applications either end up polling the interface
or relying on a user space database to maintain the DCB
state and post events. Polling is a poor solution for
obvious reasons. And relying on a user space database
has its own downside. Namely it has created strange
boot dependencies requiring the database be populated
before any applications dependent on DCB attributes
starts or the application goes into a polling loop.
Populating the database requires negotiating link
setting with the peer and can take anywhere from less
than a second up to a few seconds depending on the switch
implementation.
Perhaps more importantly if another application or an
embedded agent sets a DCB link attribute the database
has no way of knowing other than polling the kernel.
This prevents applications from responding quickly to
changes in link events which at least in the FCoE case
and probably any other protocols expecting a lossless
link may result in IO errors.
By adding a multicast group for DCB we have clean way
to disseminate kernel DCB link attributes up to user
space. Avoiding the need for user space to maintain
a coherant database and disperse events that potentially
do not reflect the current link state.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
And change iSCSI RQ doorbell size from 16B to 64B to match new firmware.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Eddie Wai <eddie.wai@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds 2 tracepoints to get a status of a socket receive queue
and related parameter.
One tracepoint is added to sock_queue_rcv_skb. It records rcvbuf size
and its usage. The other tracepoint is added to __sk_mem_schedule and
it records limitations of memory for sockets and current usage.
By using these tracepoints we're able to know detailed reason why kernel
drop the packet.
Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a tracepoint to __udp_queue_rcv_skb to get the
return value of ip_queue_rcv_skb. It indicates why kernel drops
a packet at this point.
ip_queue_rcv_skb returns following values in the packet drop case:
rcvbuf is full : -ENOMEM
sk_filter returns error : -EINVAL, -EACCESS, -ENOMEM, etc.
__sk_mem_schedule returns error: -ENOBUF
Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The PM core doesn't handle suspend failures correctly when it comes to
asynchronously suspended devices. These devices are moved onto the
dpm_suspended_list as soon as the corresponding async thread is
started up, and they remain on the list even if they fail to suspend
or the sleep transition is cancelled before they get suspended. As a
result, when the PM core unwinds the transition, it tries to resume
the devices even though they were never suspended.
This patch (as1474) fixes the problem by adding a new "is_suspended"
flag to dev_pm_info. Devices are resumed only if the flag is set.
[rjw:
* Moved the dev->power.is_suspended check into device_resume(),
because we need to complete dev->power.completion and clear
dev->power.is_prepared too for devices whose
dev->power.is_suspended flags are unset.
* Fixed __device_suspend() to avoid setting dev->power.is_suspended
if async_error is different from zero.]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
This patch (as1473) renames the "in_suspend" field in struct
dev_pm_info to "is_prepared", in preparation for an upcoming change.
The new name is more descriptive of what the field really means.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
jbd2: Fix oops in jbd2_journal_remove_journal_head()
jbd2: Remove obsolete parameters in the comments for some jbd2 functions
ext4: fixed tracepoints cleanup
ext4: use FIEMAP_EXTENT_LAST flag for last extent in fiemap
ext4: Fix max file size and logical block counting of extent format file
ext4: correct comments for ext4_free_blocks()
Some platform code has specific requirements on the naming of devices.
This patch allows callers of of_platform_populate() to provide a
device name lookup table.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
of_platform_populate() is similar to of_platform_bus_probe() except
that it strictly enforces that all device nodes must have a compatible
property, and it can be used to register devices (not buses) which are
children of the root node.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
No need for most platforms to define their own bus table when calling
of_platform_populate(). Supply a stock one.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
A few parts of the driver were missing in drivers/iommu.
Move them there to have the complete driver in that
directory.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This should ease finding similarities with different platforms,
with the intention of solving problems once in a generic framework
which everyone can use.
Note: to move intel-iommu.c, the declaration of pci_find_upstream_pcie_bridge()
has to move from drivers/pci/pci.h to include/linux/pci.h. This is handled
in this patch, too.
As suggested, also drop DMAR's EXPERIMENTAL tag while we're at it.
Compile-tested on x86_64.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Commit 13e12d14e2 ("vfs: reorganize 'struct inode' layout a bit")
moved things around a bit changed i_state to be unsigned int instead of
unsigned long. That was to help structure layout for the 64-bit case,
and shrink 'struct inode' a bit (admittedly that only happened when
spinlock debugging was on and i_flags didn't pack with i_lock).
However, Meelis Roos reports that this results in unaligned exceptions
on sprc, and it turns out that the bit-locking primitives that we use
for the I_NEW bit want to use the bitops. Which want 'unsigned long',
not 'unsigned int'.
We really should fix the bit locking code to not have that kind of
requirement, but that's a much bigger change. So for now, revert that
field back to 'unsigned long' (but keep the other re-ordering changes
from the commit that caused this).
Andi points out that we have played games with this in 'struct page', so
it's solvable with other hacks too, but since right now the struct inode
size advantage only happens with some rare config options, it's not
worth fighting.
It _would_ be worth fixing the bitlocking code, though. Especially
since there is no type safety in the bitlocking code (this never caused
any warnings, and worked fine on x86-64, because the bitlocks take a
'void *' and x86-64 doesn't care that deeply about alignment). So it's
currently a very easy problem to trigger by mistake and never notice.
Reported-by: Meelis Roos <mroos@linux.ee>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-2.6.40' of git://linux-nfs.org/~bfields/linux:
nfsd4: fix break_lease flags on nfsd open
nfsd: link returns nfserr_delay when breaking lease
nfsd: v4 support requires CRYPTO
nfsd: fix dependency of nfsd on auth_rpcgss
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (40 commits)
pxa168_eth: fix race in transmit path.
ipv4, ping: Remove duplicate icmp.h include
netxen: fix race in skb->len access
sgi-xp: fix a use after free
hp100: fix an skb->len race
netpoll: copy dev name of slaves to struct netpoll
ipv4: fix multicast losses
r8169: fix static initializers.
inet_diag: fix inet_diag_bc_audit()
gigaset: call module_put before restart of if_open()
farsync: add module_put to error path in fst_open()
net: rfs: enable RFS before first data packet is received
fs_enet: fix freescale FCC ethernet dp buffer alignment
netdev: bfin_mac: fix memory leak when freeing dma descriptors
vlan: don't call ndo_vlan_rx_register on hardware that doesn't have vlan support
caif: Bugfix - XOFF removed channel from caif-mux
tun: teach the tun/tap driver to support netpoll
dp83640: drop PHY status frames in the driver.
dp83640: fix phy status frame event parsing
phylib: Allow BCM63XX PHY to be selected only on BCM63XX.
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
devcgroup_inode_permission: take "is it a device node" checks to inlined wrapper
fix comment in generic_permission()
kill obsolete comment for follow_down()
proc_sys_permission() is OK in RCU mode
reiserfs_permission() doesn't need to bail out in RCU mode
proc_fd_permission() is doesn't need to bail out in RCU mode
nilfs2_permission() doesn't need to bail out in RCU mode
logfs doesn't need ->permission() at all
coda_ioctl_permission() is safe in RCU mode
cifs_permission() doesn't need to bail out in RCU mode
bad_inode_permission() is safe from RCU mode
ubifs: dereferencing an ERR_PTR in ubifs_mount()
Otherwise we end up overflowing the rpc buffer size on the receive end.
Signed-off-by: Benny Halevy <benny@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Function managing IRQs is needed for external drivers like b43.
On the other side we do not expect writing any hosts drivers outside of
bcma, so this is safe to do not export functions related to this.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: sh_keysc - 8x8 MODE_6 fix
Input: omap-keypad - add missing input_sync()
Input: evdev - try to wake up readers only if we have full packet
Input: properly assign return value of clamp() macro.
inode_permission() calls devcgroup_inode_permission() and almost all such
calls are _not_ for device nodes; let's at least keep the common path
straight...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add REQ_SECURE flag to REQ_COMMON_MASK so that
init_request_from_bio() can pass it to @req->cmd_flags.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@kernel.org # 2.6.36 and newer
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The comment for the skb_tx_timestamp() function suggests calling it just
after a buffer is released to the hardware for transmission. However,
for drivers that free the buffer in an ISR, this produces a race between
the time stamp code and the ISR. This commit changes the comment to advise
placing the call just before handing the buffer over to the hardware.
Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tools/perf: Fix static build of perf tool
tracing: Fix regression in printk_formats file
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
clocksource: Make watchdog robust vs. interruption
timerfd: Fix wakeup of processes when timer is cancelled on clock change
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, MAINTAINERS: Add x86 MCE people
x86, efi: Do not reserve boot services regions within reserved areas
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: Move RCU_BOOST #ifdefs to header file
rcu: use softirq instead of kthreads except when RCU_BOOST=y
rcu: Use softirq to address performance regression
rcu: Simplify curing of load woes
According to the data sheet for G4, AP4 and AG5 KEYSC MODE_6 is 8x8 keys.
Bump up MAXKEYS to 64 too.
Signed-off-by: Magnus Damm <damm@opensource.se>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
When suspending, __ieee80211_suspend() calls ieee80211_scan_cancel(),
which will only cancel sw scan. In order to cancel hw scan, the
low-level driver has to cancel it in the suspend() callback. however,
this is too late, as a new scan_work will be enqueued (while the driver
is going into suspend).
Add a new cancel_hw_scan() callback, asking the driver to cancel an
active hw scan, and call it in ieee80211_scan_cancel().
Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* 'gpio/merge' of git://git.secretlab.ca/git/linux-2.6:
gpio: add GPIOF_ values regardless on kconfig settings
gpio: include linux/gpio.h where needed
gpio/omap4: Fix missing interrupts during device wakeup due to IOPAD.
* 'spi/merge' of git://git.secretlab.ca/git/linux-2.6:
spi/bfin_spi: fix handling of default bits per word setting
____call_usermodehelper() now erases any credentials set by the
subprocess_inf::init() function. The problem is that commit
17f60a7da1 ("capabilites: allow the application of capability limits
to usermode helpers") creates and commits new credentials with
prepare_kernel_cred() after the call to the init() function. This wipes
all keyrings after umh_keys_init() is called.
The best way to deal with this is to put the init() call just prior to
the commit_creds() call, and pass the cred pointer to init(). That
means that umh_keys_init() and suchlike can modify the credentials
_before_ they are published and potentially in use by the rest of the
system.
This prevents request_key() from working as it is prevented from passing
the session keyring it set up with the authorisation token to
/sbin/request-key, and so the latter can't assume the authority to
instantiate the key. This causes the in-kernel DNS resolver to fail
with ENOKEY unconditionally.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a problem that kdump(2nd kernel) sometimes hangs up due
to a pending IPI from 1st kernel. Kernel panic occurs because IPI
comes before call_single_queue is initialized.
To fix the crash, rename init_call_single_data() to call_function_init()
and call it in start_kernel() so that call_single_queue can be
initialized before enabling interrupts.
The details of the crash are:
(1) 2nd kernel boots up
(2) A pending IPI from 1st kernel comes when irqs are first enabled
in start_kernel().
(3) Kernel tries to handle the interrupt, but call_single_queue
is not initialized yet at this point. As a result, in the
generic_smp_call_function_single_interrupt(), NULL pointer
dereference occurs when list_replace_init() tries to access
&q->list.next.
Therefore this patch changes the name of init_call_single_data()
to call_function_init() and calls it before local_irq_enable()
in start_kernel().
Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Milton Miller <miltonm@bga.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: kexec@lists.infradead.org
Link: http://lkml.kernel.org/r/D6CBEE2F420741indou.takao@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/radeon/kms: use helper functions for fence read/write
drm/radeon/kms: set DP link config properly for DP bridges
drm/radeon/kms/atom: AdjustPixelClock fixes for DP bridges
drm/radeon/kms: fix handling of DP to LVDS bridges
drm/radeon/kms: issue blank/unblank commands for ext encoders
drm/radeon/kms: fix support for DDC on dp bridges
drm/radeon/kms: add support for load detection on dp bridges
drm/radeon/kms: add missing external encoder action
drm/radeon/kms: rework atombios_get_encoder_mode()
drm/radeon/kms: fix num crtcs for Cedar and Caicos
Revert "drm/i915: Enable GMBUS for post-gen2 chipsets"
drivers/gpu/drm: use printk_ratelimited instead of printk_ratelimit
drm/radeon: workaround a hw bug on some radeon chipsets with all-0 EDIDs.
drm: make debug levels match in edid failure code.
drm/radeon/kms: clear wb memory by default
drm/radeon/kms: be more pedantic about the g5 quirk (v2)
drm/radeon/kms: signed fix for evergreen thermal
drm: populate irq_by_busid-member for pci
Instead of setting bits manually we use set_bit, test_bit, etc.
Also remove L2CAP_ prefix from macros.
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Management interface commands for blocking and unblocking devices.
Signed-off-by: Antti Julku <antti.julku@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
The previous patch implemented async notification for ptrace but it
only worked while trace is running. This patch introduces
PTRACE_LISTEN which is suggested by Oleg Nestrov.
It's allowed iff tracee is in STOP trap and puts tracee into
quasi-running state - tracee never really runs but wait(2) and
ptrace(2) consider it to be running. While ptracer is listening,
tracee is allowed to re-enter STOP to notify an async event.
Listening state is cleared on the first notification. Ptracer can
also clear it by issuing INTERRUPT - tracee will re-trap into STOP
with listening state cleared.
This allows ptracer to monitor group stop state without running tracee
- use INTERRUPT to put tracee into STOP trap, issue LISTEN and then
wait(2) to wait for the next group stop event. When it happens,
PTRACE_GETSIGINFO provides information to determine the current state.
Test program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_INTERRUPT 0x4207
#define PTRACE_LISTEN 0x4208
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts1s = { .tv_sec = 1 };
int main(int argc, char **argv)
{
pid_t tracee, tracer;
int i;
tracee = fork();
if (!tracee)
while (1)
pause();
tracer = fork();
if (!tracer) {
siginfo_t si;
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
ptrace(PTRACE_INTERRUPT, tracee, NULL, NULL);
repeat:
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_GETSIGINFO, tracee, NULL, &si);
if (!si.si_code) {
printf("tracer: SIG %d\n", si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL,
(void *)(unsigned long)si.si_signo);
goto repeat;
}
printf("tracer: stopped=%d signo=%d\n",
si.si_signo != SIGTRAP, si.si_signo);
if (si.si_signo != SIGTRAP)
ptrace(PTRACE_LISTEN, tracee, NULL, NULL);
else
ptrace(PTRACE_CONT, tracee, NULL, NULL);
goto repeat;
}
for (i = 0; i < 3; i++) {
nanosleep(&ts1s, NULL);
printf("mother: SIGSTOP\n");
kill(tracee, SIGSTOP);
nanosleep(&ts1s, NULL);
printf("mother: SIGCONT\n");
kill(tracee, SIGCONT);
}
nanosleep(&ts1s, NULL);
kill(tracer, SIGKILL);
kill(tracee, SIGKILL);
return 0;
}
This is identical to the program to test TRAP_NOTIFY except that
tracee is PTRACE_LISTEN'd instead of PTRACE_CONT'd when group stopped.
This allows ptracer to monitor when group stop ends without running
tracee.
# ./test-listen
tracer: stopped=0 signo=5
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
-v2: Moved JOBCTL_LISTENING check in wait_task_stopped() into
task_stopped_code() as suggested by Oleg.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Currently there's no way for ptracer to find out whether group stop
finished other than polling with INTERRUPT - GETSIGINFO - CONT
sequence. This patch implements group stop notification for ptracer
using STOP traps.
When group stop state of a seized tracee changes, JOBCTL_TRAP_NOTIFY
is set, which schedules a STOP trap which is sticky - it isn't cleared
by other traps and at least one STOP trap will happen eventually.
STOP trap is synchronization point for event notification and the
tracer can determine the current group stop state by looking at the
signal number portion of exit code (si_status from waitid(2) or
si_code from PTRACE_GETSIGINFO).
Notifications are generated both on start and end of group stops but,
because group stop participation always happens before STOP trap, this
doesn't cause an extra trap while tracee is participating in group
stop. The symmetry will be useful later.
Note that this notification works iff tracee is not trapped.
Currently there is no way to be notified of group stop state changes
while tracee is trapped. This will be addressed by a later patch.
An example program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_INTERRUPT 0x4207
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts1s = { .tv_sec = 1 };
int main(int argc, char **argv)
{
pid_t tracee, tracer;
int i;
tracee = fork();
if (!tracee)
while (1)
pause();
tracer = fork();
if (!tracer) {
siginfo_t si;
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
ptrace(PTRACE_INTERRUPT, tracee, NULL, NULL);
repeat:
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_GETSIGINFO, tracee, NULL, &si);
if (!si.si_code) {
printf("tracer: SIG %d\n", si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL,
(void *)(unsigned long)si.si_signo);
goto repeat;
}
printf("tracer: stopped=%d signo=%d\n",
si.si_signo != SIGTRAP, si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL, NULL);
goto repeat;
}
for (i = 0; i < 3; i++) {
nanosleep(&ts1s, NULL);
printf("mother: SIGSTOP\n");
kill(tracee, SIGSTOP);
nanosleep(&ts1s, NULL);
printf("mother: SIGCONT\n");
kill(tracee, SIGCONT);
}
nanosleep(&ts1s, NULL);
kill(tracer, SIGKILL);
kill(tracee, SIGKILL);
return 0;
}
In the above program, tracer keeps tracee running and gets
notification of each group stop state changes.
# ./test-notify
tracer: stopped=0 signo=5
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
