From 76d5692a58031696e282384cbd893832bc92bd76 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 9 Feb 2017 15:43:44 -0800 Subject: pstore: Correctly initialize spinlock and flags The ram backend wasn't always initializing its spinlock correctly. Since it was coming from kzalloc memory, though, it was harmless on architectures that initialize unlocked spinlocks to 0 (at least x86 and ARM). This also fixes a possibly ignored flag setting too. When running under CONFIG_DEBUG_SPINLOCK, the following Oops was visible: [ 0.760836] persistent_ram: found existing buffer, size 29988, start 29988 [ 0.765112] persistent_ram: found existing buffer, size 30105, start 30105 [ 0.769435] persistent_ram: found existing buffer, size 118542, start 118542 [ 0.785960] persistent_ram: found existing buffer, size 0, start 0 [ 0.786098] persistent_ram: found existing buffer, size 0, start 0 [ 0.786131] pstore: using zlib compression [ 0.790716] BUG: spinlock bad magic on CPU#0, swapper/0/1 [ 0.790729] lock: 0xffffffc0d1ca9bb0, .magic: 00000000, .owner: /-1, .owner_cpu: 0 [ 0.790742] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc2+ #913 [ 0.790747] Hardware name: Google Kevin (DT) [ 0.790750] Call trace: [ 0.790768] [] dump_backtrace+0x0/0x2bc [ 0.790780] [] show_stack+0x20/0x28 [ 0.790794] [] dump_stack+0xa4/0xcc [ 0.790809] [] spin_dump+0xe0/0xf0 [ 0.790821] [] spin_bug+0x30/0x3c [ 0.790834] [] do_raw_spin_lock+0x50/0x1b8 [ 0.790846] [] _raw_spin_lock_irqsave+0x54/0x6c [ 0.790862] [] buffer_size_add+0x48/0xcc [ 0.790875] [] persistent_ram_write+0x60/0x11c [ 0.790888] [] ramoops_pstore_write_buf+0xd4/0x2a4 [ 0.790900] [] pstore_console_write+0xf0/0x134 [ 0.790912] [] console_unlock+0x48c/0x5e8 [ 0.790923] [] register_console+0x3b0/0x4d4 [ 0.790935] [] pstore_register+0x1a8/0x234 [ 0.790947] [] ramoops_probe+0x6b8/0x7d4 [ 0.790961] [] platform_drv_probe+0x7c/0xd0 [ 0.790972] [] driver_probe_device+0x1b4/0x3bc [ 0.790982] [] __device_attach_driver+0xc8/0xf4 [ 0.790996] [] bus_for_each_drv+0xb4/0xe4 [ 0.791006] [] __device_attach+0xd0/0x158 [ 0.791016] [] device_initial_probe+0x24/0x30 [ 0.791026] [] bus_probe_device+0x50/0xe4 [ 0.791038] [] device_add+0x3a4/0x76c [ 0.791051] [] of_device_add+0x74/0x84 [ 0.791062] [] of_platform_device_create_pdata+0xc0/0x100 [ 0.791073] [] of_platform_device_create+0x34/0x40 [ 0.791086] [] of_platform_default_populate_init+0x58/0x78 [ 0.791097] [] do_one_initcall+0x88/0x160 [ 0.791109] [] kernel_init_freeable+0x264/0x31c [ 0.791123] [] kernel_init+0x18/0x11c [ 0.791133] [] ret_from_fork+0x10/0x50 [ 0.793717] console [pstore-1] enabled [ 0.797845] pstore: Registered ramoops as persistent store backend [ 0.804647] ramoops: attached 0x100000@0xf7edc000, ecc: 0/0 Fixes: 663deb47880f ("pstore: Allow prz to control need for locking") Fixes: 109704492ef6 ("pstore: Make spinlock per zone instead of global") Reported-by: Brian Norris Signed-off-by: Kees Cook --- fs/pstore/ram_core.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index a857338b7dab..bc927e30bdcc 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -467,8 +467,7 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size, } static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, - struct persistent_ram_ecc_info *ecc_info, - unsigned long flags) + struct persistent_ram_ecc_info *ecc_info) { int ret; @@ -494,10 +493,9 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, prz->buffer->sig); } + /* Rewind missing or invalid memory area. */ prz->buffer->sig = sig; persistent_ram_zap(prz); - prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); - prz->flags = flags; return 0; } @@ -533,11 +531,15 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size, goto err; } + /* Initialize general buffer state. */ + prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); + prz->flags = flags; + ret = persistent_ram_buffer_map(start, size, prz, memtype); if (ret) goto err; - ret = persistent_ram_post_init(prz, sig, ecc_info, flags); + ret = persistent_ram_post_init(prz, sig, ecc_info); if (ret) goto err; -- cgit v1.2.3-59-g8ed1b From 46418413ed200aa2c856a4426f93a157672b10c7 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 10 Feb 2017 10:15:34 -0800 Subject: pstore: Check for prz allocation in walker Instead of needing additional checks in callers for unallocated przs, perform the check in the walker, which gives us a more universal way to handle the situation. Signed-off-by: Kees Cook --- fs/pstore/ram.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 1d887efaaf71..11f918d34b1e 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -133,7 +133,8 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max, struct persistent_ram_zone *prz; int i = (*c)++; - if (i >= max) + /* Give up if we never existed or have hit the end. */ + if (!przs || i >= max) return NULL; prz = przs[i]; @@ -280,7 +281,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, 1, id, type, PSTORE_TYPE_PMSG, 0); /* ftrace is last since it may want to dynamically allocate memory. */ - if (!prz_ok(prz) && cxt->fprzs) { + if (!prz_ok(prz)) { if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) { prz = ramoops_get_next_prz(cxt->fprzs, &cxt->ftrace_read_cnt, 1, id, type, -- cgit v1.2.3-59-g8ed1b From fc1b326efd276e7d121f5c1ced2884ae52a85814 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 10 Feb 2017 10:19:07 -0800 Subject: MAINTAINERS: Adjust pstore git repo URI, add files The tree used for staging pstore changes has moved to my repo. The -next tree already pulls from here, so update MAINTAINERS to reflect reality. While at it, add some more pstore-related files to track. Signed-off-by: Kees Cook --- MAINTAINERS | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 107c10e8f2d2..b135644f8a60 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9968,16 +9968,19 @@ S: Maintained F: drivers/block/ps3vram.c PSTORE FILESYSTEM +M: Kees Cook M: Anton Vorontsov M: Colin Cross -M: Kees Cook M: Tony Luck S: Maintained -T: git git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux.git +T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore F: fs/pstore/ F: include/linux/pstore* F: drivers/firmware/efi/efi-pstore.c F: drivers/acpi/apei/erst.c +F: Documentation/admin-guide/ramoops.rst +F: Documentation/devicetree/bindings/reserved-memory/ramoops.txt +K: \b(pstore|ramoops) PTP HARDWARE CLOCK SUPPORT M: Richard Cochran -- cgit v1.2.3-59-g8ed1b