- 16 Jan, 2011 24 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6Linus Torvalds authored
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (23 commits) sanitize vfsmount refcounting changes fix old umount_tree() breakage autofs4: Merge the remaining dentry ops tables Unexport do_add_mount() and add in follow_automount(), not ->d_automount() Allow d_manage() to be used in RCU-walk mode Remove a further kludge from __do_follow_link() autofs4: Bump version autofs4: Add v4 pseudo direct mount support autofs4: Fix wait validation autofs4: Clean up autofs4_free_ino() autofs4: Clean up dentry operations autofs4: Clean up inode operations autofs4: Remove unused code autofs4: Add d_manage() dentry operation autofs4: Add d_automount() dentry operation Remove the automount through follow_link() kludge code from pathwalk CIFS: Use d_automount() rather than abusing follow_link() NFS: Use d_automount() rather than abusing follow_link() AFS: Use d_automount() rather than abusing follow_link() Add an AT_NO_AUTOMOUNT flag to suppress terminal automount ...
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Al Viro authored
Instead of splitting refcount between (per-cpu) mnt_count and (SMP-only) mnt_longrefs, make all references contribute to mnt_count again and keep track of how many are longterm ones. Accounting rules for longterm count: * 1 for each fs_struct.root.mnt * 1 for each fs_struct.pwd.mnt * 1 for having non-NULL ->mnt_ns * decrement to 0 happens only under vfsmount lock exclusive That allows nice common case for mntput() - since we can't drop the final reference until after mnt_longterm has reached 0 due to the rules above, mntput() can grab vfsmount lock shared and check mnt_longterm. If it turns out to be non-zero (which is the common case), we know that this is not the final mntput() and can just blindly decrement percpu mnt_count. Otherwise we grab vfsmount lock exclusive and do usual decrement-and-check of percpu mnt_count. For fs_struct.c we have mnt_make_longterm() and mnt_make_shortterm(); namespace.c uses the latter in places where we don't already hold vfsmount lock exclusive and opencodes a few remaining spots where we need to manipulate mnt_longterm. Note that we mostly revert the code outside of fs/namespace.c back to what we used to have; in particular, normal code doesn't need to care about two kinds of references, etc. And we get to keep the optimization Nick's variant had bought us... Signed-off-by:Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Expiry-related code calls umount_tree() several times with the same list to collect vfsmounts to. Which is fine, except that umount_tree() implicitly assumed that the list would be empty on each call - it moves the victims over there and then iterates through the list kicking them out. It's *almost* idempotent, so everything nearly worked. However, mnt->ghosts handling (and thus expirability checks) had been broken - that part was not idempotent... The fix is trivial - use local temporary list, splice it to the the collector list when we are through. Signed-off-by: -
David Howells authored
Merge the remaining autofs4 dentry ops tables. It doesn't matter if d_automount and d_manage are present on something that's not mountable or holdable as these ops are only used if the appropriate flags are set in dentry->d_flags. [AV] switch to ->s_d_op, since now _everything_ on autofs4 is using the same dentry_operations. Signed-off-by:
David Howells <dhowells@redhat.com> Signed-off-by:
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David Howells authored
Unexport do_add_mount() and make ->d_automount() return the vfsmount to be added rather than calling do_add_mount() itself. follow_automount() will then do the addition. This slightly complicates things as ->d_automount() normally wants to add the new vfsmount to an expiration list and start an expiration timer. The problem with that is that the vfsmount will be deleted if it has a refcount of 1 and the timer will not repeat if the expiration list is empty. To this end, we require the vfsmount to be returned from d_automount() with a refcount of (at least) 2. One of these refs will be dropped unconditionally. In addition, follow_automount() must get a 3rd ref around the call to do_add_mount() lest it eat a ref and return an error, leaving the mount we have open to being expired as we would otherwise have only 1 ref on it. d_automount() should also add the the vfsmount to the expiration list (by calling mnt_set_expiry()) and start the expiration timer before returning, if this mechanism is to be used. The vfsmount will be unlinked from the expiration list by follow_automount() if do_add_mount() fails. This patch also fixes the call to do_add_mount() for AFS to propagate the mount flags from the parent vfsmount. Signed-off-by:
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David Howells authored
Allow d_manage() to be called from pathwalk when it is in RCU-walk mode as well as when it is in Ref-walk mode. This permits __follow_mount_rcu() to call d_manage() directly. d_manage() needs a parameter to indicate that it is in RCU-walk mode as it isn't allowed to sleep if in that mode (but should return -ECHILD instead). autofs4_d_manage() can then be set to retain RCU-walk mode if the daemon accesses it and otherwise request dropping back to ref-walk mode. Signed-off-by:
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David Howells authored
Remove a further kludge from __do_follow_link() as it's no longer required with the automount code. This reverts the non-helper-function parts of 051d3812, which breaks union mounts. Reported-by: vaurora@redhat.com Signed-off-by:
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Ian Kent authored
Increase the autofs module sub-version so we can tell what kernel implementation is being used from user space debug logging. Signed-off-by:
Ian Kent <raven@themaw.net> Signed-off-by:
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Ian Kent authored
Version 4 of autofs provides a pseudo direct mount implementation that relies on directories at the leaves of a directory tree under an indirect mount to trigger mounts. This patch adds support for that functionality. Signed-off-by:
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Ian Kent authored
It is possible for the check in wait.c:validate_request() to return an incorrect result if the dentry that was mounted upon has changed during the callback. Signed-off-by:
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Ian Kent authored
When this function is called the local reference count does't need to be updated since the dentry is going away and dput definitely must not be called here. Also the autofs info struct field inode isn't used so remove it. Signed-off-by:
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Ian Kent authored
There are now two distinct dentry operations uses. One for dentrys that trigger mounts and one for dentrys that do not. Rationalize the use of these dentry operations and rename them to reflect their function. Signed-off-by:
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Ian Kent authored
Since the use of ->follow_link() has been eliminated there is no need to separate the indirect and direct inode operations. Signed-off-by:
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Ian Kent authored
Remove code that is not used due to the use of ->d_automount() and ->d_manage(). Signed-off-by:
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Ian Kent authored
This patch required a previous patch to add the ->d_automount() dentry operation. Add a function to use the newly defined ->d_manage() dentry operation for blocking during mount and expire. Whether the VFS calls the dentry operations d_automount() and d_manage() is controled by the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags. autofs uses the d_automount() operation to callback to user space to request mount operations and the d_manage() operation to block walks into mounts that are under construction or destruction. In order to prevent these functions from being called unnecessarily the DMANAGED_* flags are cleared for cases which would cause this. In the common case the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags are both set for dentrys waiting to be mounted. The DMANAGED_TRANSIT flag is cleared upon successful mount request completion and set during expire runs, both during the dentry expire check, and if selected for expire, is left set until a subsequent successful mount request completes. The exception to this is the so-called rootless multi-mount which has no actual mount at its base. In this case the DMANAGED_AUTOMOUNT flag is cleared upon successful mount request completion as well and set again after a successful expire. Signed-off-by:
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Ian Kent authored
Add a function to use the newly defined ->d_automount() dentry operation for triggering mounts instead of doing the user space callback in ->lookup() and ->d_revalidate(). Note, to be useful the subsequent patch to add the ->d_manage() dentry operation is also needed so the discussion of functionality is deferred to that patch. Signed-off-by:
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David Howells authored
Remove the automount through follow_link() kludge code from pathwalk in favour of using d_automount(). Signed-off-by:
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David Howells authored
Make CIFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. [NOTE: THIS IS UNTESTED!] Signed-off-by:
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David Howells authored
Make NFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. Signed-off-by:
Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by:
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David Howells authored
Make AFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. Signed-off-by:
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David Howells authored
Add an AT_NO_AUTOMOUNT flag to suppress terminal automounting of automount point directories. This can be used by fstatat() users to permit the gathering of attributes on an automount point and also prevent mass-automounting of a directory of automount points by ls. Signed-off-by:
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David Howells authored
Add a dentry op (d_manage) to permit a filesystem to hold a process and make it sleep when it tries to transit away from one of that filesystem's directories during a pathwalk. The operation is keyed off a new dentry flag (DCACHE_MANAGE_TRANSIT). The filesystem is allowed to be selective about which processes it holds and which it permits to continue on or prohibits from transiting from each flagged directory. This will allow autofs to hold up client processes whilst letting its userspace daemon through to maintain the directory or the stuff behind it or mounted upon it. The ->d_manage() dentry operation: int (*d_manage)(struct path *path, bool mounting_here); takes a pointer to the directory about to be transited away from and a flag indicating whether the transit is undertaken by do_add_mount() or do_move_mount() skipping through a pile of filesystems mounted on a mountpoint. It should return 0 if successful and to let the process continue on its way; -EISDIR to prohibit the caller from skipping to overmounted filesystems or automounting, and to use this directory; or some other error code to return to the user. ->d_manage() is called with namespace_sem writelocked if mounting_here is true and no other locks held, so it may sleep. However, if mounting_here is true, it may not initiate or wait for a mount or unmount upon the parameter directory, even if the act is actually performed by userspace. Within fs/namei.c, follow_managed() is extended to check with d_manage() first on each managed directory, before transiting away from it or attempting to automount upon it. follow_down() is renamed follow_down_one() and should only be used where the filesystem deliberately intends to avoid management steps (e.g. autofs). A new follow_down() is added that incorporates the loop done by all other callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS and CIFS do use it, their use is removed by converting them to use d_automount()). The new follow_down() calls d_manage() as appropriate. It also takes an extra parameter to indicate if it is being called from mount code (with namespace_sem writelocked) which it passes to d_manage(). follow_down() ignores automount points so that it can be used to mount on them. __follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to sleep. It would be possible to enter d_manage() in rcu-walk mode too, and have that determine whether to abort or not itself. That would allow the autofs daemon to continue on in rcu-walk mode. Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't required as every tranist from that directory will cause d_manage() to be invoked. It can always be set again when necessary. ========================== WHAT THIS MEANS FOR AUTOFS ========================== Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to trigger the automounting of indirect mounts, and both of these can be called with i_mutex held. autofs knows that the i_mutex will be held by the caller in lookup(), and so can drop it before invoking the daemon - but this isn't so for d_revalidate(), since the lock is only held on _some_ of the code paths that call it. This means that autofs can't risk dropping i_mutex from its d_revalidate() function before it calls the daemon. The bug could manifest itself as, for example, a process that's trying to validate an automount dentry that gets made to wait because that dentry is expired and needs cleaning up: mkdir S ffffffff8014e05a 0 32580 24956 Call Trace: [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f [<ffffffff80057a2f>] lookup_create+0x46/0x80 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4 versus the automount daemon which wants to remove that dentry, but can't because the normal process is holding the i_mutex lock: automount D ffffffff8014e05a 0 32581 1 32561 Call Trace: [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14 [<ffffffff800e6d55>] do_rmdir+0x77/0xde [<ffffffff8005d229>] tracesys+0x71/0xe0 [<ffffffff8005d28d>] tracesys+0xd5/0xe0 which means that the system is deadlocked. This patch allows autofs to hold up normal processes whilst the daemon goes ahead and does things to the dentry tree behind the automouter point without risking a deadlock as almost no locks are held in d_manage() and none in d_automount(). Signed-off-by:
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David Howells authored
Add a dentry op (d_automount) to handle automounting directories rather than abusing the follow_link() inode operation. The operation is keyed off a new dentry flag (DCACHE_NEED_AUTOMOUNT). This also makes it easier to add an AT_ flag to suppress terminal segment automount during pathwalk and removes the need for the kludge code in the pathwalk algorithm to handle directories with follow_link() semantics. The ->d_automount() dentry operation: struct vfsmount *(*d_automount)(struct path *mountpoint); takes a pointer to the directory to be mounted upon, which is expected to provide sufficient data to determine what should be mounted. If successful, it should return the vfsmount struct it creates (which it should also have added to the namespace using do_add_mount() or similar). If there's a collision with another automount attempt, NULL should be returned. If the directory specified by the parameter should be used directly rather than being mounted upon, -EISDIR should be returned. In any other case, an error code should be returned. The ->d_automount() operation is called with no locks held and may sleep. At this point the pathwalk algorithm will be in ref-walk mode. Within fs/namei.c itself, a new pathwalk subroutine (follow_automount()) is added to handle mountpoints. It will return -EREMOTE if the automount flag was set, but no d_automount() op was supplied, -ELOOP if we've encountered too many symlinks or mountpoints, -EISDIR if the walk point should be used without mounting and 0 if successful. The path will be updated to point to the mounted filesystem if a successful automount took place. __follow_mount() is replaced by follow_managed() which is more generic (especially with the patch that adds ->d_manage()). This handles transits from directories during pathwalk, including automounting and skipping over mountpoints (and holding processes with the next patch). __follow_mount_rcu() will jump out of RCU-walk mode if it encounters an automount point with nothing mounted on it. follow_dotdot*() does not handle automounts as you don't want to trigger them whilst following "..". I've also extracted the mount/don't-mount logic from autofs4 and included it here. It makes the mount go ahead anyway if someone calls open() or creat(), tries to traverse the directory, tries to chdir/chroot/etc. into the directory, or sticks a '/' on the end of the pathname. If they do a stat(), however, they'll only trigger the automount if they didn't also say O_NOFOLLOW. I've also added an inode flag (S_AUTOMOUNT) so that filesystems can mark their inodes as automount points. This flag is automatically propagated to the dentry as DCACHE_NEED_AUTOMOUNT by __d_instantiate(). This saves NFS and could save AFS a private flag bit apiece, but is not strictly necessary. It would be preferable to do the propagation in d_set_d_op(), but that doesn't normally have access to the inode. [AV: fixed breakage in case if __follow_mount_rcu() fails and nameidata_drop_rcu() succeeds in RCU case of do_lookup(); we need to fall through to non-RCU case after that, rather than just returning with ungrabbed *path] Signed-off-by:
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Al Viro authored
do_lookup() has a path leading from LOOKUP_RCU case to non-RCU crossing of mountpoints, which breaks things badly. If we hit need_revalidate: and do nothing in there, we need to come back into LOOKUP_RCU half of things, not to done: in non-RCU one. Signed-off-by:
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- 15 Jan, 2011 16 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6Linus Torvalds authored
* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: Update Pekka's email address in MAINTAINERS mm/slab.c: make local symbols static slub: Avoid use of slub_lock in show_slab_objects() memory hotplug: one more lock on memory hotplug
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Linus Torvalds authored
Merge branches 'core-fixes-for-linus', 'x86-fixes-for-linus', 'timers-fixes-for-linus' and 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: avoid pointless blocked-task warnings rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status rtmutex: Fix comment about why new_owner can be NULL in wake_futex_pi() * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, olpc: Add missing Kconfig dependencies x86, mrst: Set correct APB timer IRQ affinity for secondary cpu x86: tsc: Fix calibration refinement conditionals to avoid divide by zero x86, ia64, acpi: Clean up x86-ism in drivers/acpi/numa.c * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timekeeping: Make local variables static time: Rename misnamed minsec argument of clocks_calc_mult_shift() * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Remove syscall_exit_fields tracing: Only process module tracepoints once perf record: Add "nodelay" mode, disabled by default perf sched: Fix list of events, dropping unsupported ':r' modifier Revert "perf tools: Emit clearer message for sys_perf_event_open ENOENT return" perf top: Fix annotate segv perf evsel: Fix order of event list deletion
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Linus Torvalds authored
* 'devel-stable' of master.kernel.org:/home/rmk/linux-2.6-arm: (161 commits) ARM: pxa: fix building issue of missing physmap.h ARM: mmp: PXA910 drive strength FAST using wrong value ARM: mmp: MMP2 drive strength FAST using wrong value ARM: pxa: fix recursive calls in pxa_low_gpio_chip AT91: Support for gsia18s board AT91: Acme Systems FOX Board G20 board files AT91: board-sam9m10g45ek.c: Remove duplicate inclusion of mach/hardware.h ARM: pxa: fix suspend/resume array index miscalculation ARM: pxa: use cpu_has_ipr() consistently in irq.c ARM: pxa: remove unused variable in clock-pxa3xx.c ARM: pxa: fix warning in zeus.c ARM: sa1111: fix typo in sa1111_retrigger_lowirq() ARM mxs: clkdev related compile fixes ARM i.MX mx31_3ds: Fix MC13783 regulator names ARM: plat-stmp3xxx: irq_data conversion. ARM: plat-spear: irq_data conversion. ARM: plat-orion: irq_data conversion. ARM: plat-omap: irq_data conversion. ARM: plat-nomadik: irq_data conversion. ARM: plat-mxc: irq_data conversion. ... Fix up trivial conflict in arch/arm/plat-omap/gpio.c (Lennert Buytenhek's irq_data conversion clashing with some omap irq updates)
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Linus Torvalds authored
* 'fixes' of master.kernel.org:/home/rmk/linux-2.6-arm: ARM: fix missing branch in __error_a ARM: fix /proc/$PID/stack on SMP ARM: Fix build regression on SA11x0, PXA, and H720x targets ARM: 6625/1: use memblock memory regions for "System RAM" I/O resources ARM: fix wrongly patched constants ARM: 6624/1: fix dependency for CONFIG_SMP_ON_UP ARM: 6623/1: Thumb-2: Fix out-of-range offset for Thumb-2 in proc-v7.S ARM: 6622/1: fix dma_unmap_sg() documentation ARM: 6621/1: bitops: remove condition code clobber for CLZ ARM: 6620/1: Change misleading warning when CONFIG_CMDLINE_FORCE is used ARM: 6619/1: nommu: avoid mapping vectors page when !CONFIG_MMU ARM: sched_clock: make minsec argument to clocks_calc_mult_shift() zero ARM: sched_clock: allow init_sched_clock() to be called early ARM: integrator: fix compile warning in cpu.c ARM: 6616/1: Fix ep93xx-fb init/exit annotations ARM: twd: fix display of twd frequency ARM: udelay: prevent math rounding resulting in short udelays
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Ingo Molnar authored
Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/urgent
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Russell King authored
Merge branch 'for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung into devel-stable
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Russell King authored
Merge branch 'devel' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6 into devel-stable
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Pekka Enberg authored
Signed-off-by:Pekka Enberg <penberg@kernel.org>
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H Hartley Sweeten authored
Local symbols should be static. Signed-off-by:
H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by:
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Pekka Enberg authored
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Russell King authored
When DEBUG_LL is not set, we don't want __error_a re-entering __lookup_machine_type - we want it to go to the error function. This used to be the case before we reorganized the layout for hotplug cpu, as we used to fall through to __error. With the changed layout, we need an explicit branch here instead. Signed-off-by:Russell King <rmk+kernel@arm.linux.org.uk>
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Eric Miao authored
Signed-off-by:Eric Miao <eric.y.miao@gmail.com>
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Philip Rakity authored
Drive strength for PXA910 is a 2 bit value but because of the mapping in plat-pxa/mfp.h needs to be shifted up one bit to handle real location in mfp registers. (MMP2 and PXA910 drive strength start at bit 11 while PXA168 starts at bit 10). Values 0, 1, 2, and 3 effectively need to be 0, 2, 4, and 6 to fit into register. 8 does not work. Signed-off-by:
Philip Rakity <prakity@marvell.com> Signed-off-by:
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Philip Rakity authored
Drive strength for MMP2 is a 2 bit value but because of the mapping in plat-pxa/mfp.h needs to be shifted up one bit to handle real location in mfp registers. (MMP2 and PXA910 drive strength start at bit 11 while PXA168 starts at bit 10). Values 0, 1, 2, and 3 effectively need to be 0, 2, 4, and 6 to fit into register. 8 does not work. Signed-off-by:
John Watlington <wad@laptop.org> Signed-off-by:
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Eric Miao authored
Signed-off-by:
Marek Vasut <marek.vasut@gmail.com>
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Russell King authored
Rabin Vincent reports: | On SMP, this BUG() in save_stack_trace_tsk() can be easily triggered | from user space by reading /proc/$PID/stack, where $PID is any pid but | the current process: | | if (tsk != current) { | #ifdef CONFIG_SMP | /* | * What guarantees do we have here that 'tsk' | * is not running on another CPU? | */ | BUG(); | #else Fix this by replacing the BUG() with an entry to terminate the stack trace, returning an empty trace - I'd rather not expose the dwarf unwinder to a volatile stack of a running thread. Reported-by:Rabin Vincent <rabin@rab.in> Tested-by:
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