user/sven/linux.git/drivers/dma/dmaengine.c, branch v6.2.7

dmaengine: Fix double increment of client_count in dma_chan_get()

2023-01-18T12:06:49Z

The first time dma_chan_get() is called for a channel the channel client_count is incorrectly incremented twice for public channels, first in balance_ref_count(), and again prior to returning. This results in an incorrect client count which will lead to the channel resources not being freed when they should be. A simple test of repeated module load and unload of async_tx on a Dell Power Edge R7425 also shows this resulting in a kref underflow warning. [ 124.329662] async_tx: api initialized (async) [ 129.000627] async_tx: api initialized (async) [ 130.047839] ------------[ cut here ]------------ [ 130.052472] refcount_t: underflow; use-after-free. [ 130.057279] WARNING: CPU: 3 PID: 19364 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x110 [ 130.065811] Modules linked in: async_tx(-) rfkill intel_rapl_msr intel_rapl_common amd64_edac edac_mce_amd ipmi_ssif kvm_amd dcdbas kvm mgag200 drm_shmem_helper acpi_ipmi irqbypass drm_kms_helper ipmi_si syscopyarea sysfillrect rapl pcspkr ipmi_devintf sysimgblt fb_sys_fops k10temp i2c_piix4 ipmi_msghandler acpi_power_meter acpi_cpufreq vfat fat drm fuse xfs libcrc32c sd_mod t10_pi sg ahci crct10dif_pclmul libahci crc32_pclmul crc32c_intel ghash_clmulni_intel igb megaraid_sas i40e libata i2c_algo_bit ccp sp5100_tco dca dm_mirror dm_region_hash dm_log dm_mod [last unloaded: async_tx] [ 130.117361] CPU: 3 PID: 19364 Comm: modprobe Kdump: loaded Not tainted 5.14.0-185.el9.x86_64 #1 [ 130.126091] Hardware name: Dell Inc. PowerEdge R7425/02MJ3T, BIOS 1.18.0 01/17/2022 [ 130.133806] RIP: 0010:refcount_warn_saturate+0xba/0x110 [ 130.139041] Code: 01 01 e8 6d bd 55 00 0f 0b e9 72 9d 8a 00 80 3d 26 18 9c 01 00 75 85 48 c7 c7 f8 a3 03 9d c6 05 16 18 9c 01 01 e8 4a bd 55 00 <0f> 0b e9 4f 9d 8a 00 80 3d 01 18 9c 01 00 0f 85 5e ff ff ff 48 c7 [ 130.157807] RSP: 0018:ffffbf98898afe68 EFLAGS: 00010286 [ 130.163036] RAX: 0000000000000000 RBX: ffff9da06028e598 RCX: 0000000000000000 [ 130.170172] RDX: ffff9daf9de26480 RSI: ffff9daf9de198a0 RDI: ffff9daf9de198a0 [ 130.177316] RBP: ffff9da7cddf3970 R08: 0000000000000000 R09: 00000000ffff7fff [ 130.184459] R10: ffffbf98898afd00 R11: ffffffff9d9e8c28 R12: ffff9da7cddf1970 [ 130.191596] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 130.198739] FS: 00007f646435c740(0000) GS:ffff9daf9de00000(0000) knlGS:0000000000000000 [ 130.206832] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 130.212586] CR2: 00007f6463b214f0 CR3: 00000008ab98c000 CR4: 00000000003506e0 [ 130.219729] Call Trace: [ 130.222192] [ 130.224305] dma_chan_put+0x10d/0x110 [ 130.227988] dmaengine_put+0x7a/0xa0 [ 130.231575] __do_sys_delete_module.constprop.0+0x178/0x280 [ 130.237157] ? syscall_trace_enter.constprop.0+0x145/0x1d0 [ 130.242652] do_syscall_64+0x5c/0x90 [ 130.246240] ? exc_page_fault+0x62/0x150 [ 130.250178] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 130.255243] RIP: 0033:0x7f6463a3f5ab [ 130.258830] Code: 73 01 c3 48 8b 0d 75 a8 1b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 45 a8 1b 00 f7 d8 64 89 01 48 [ 130.277591] RSP: 002b:00007fff22f972c8 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 [ 130.285164] RAX: ffffffffffffffda RBX: 000055b6786edd40 RCX: 00007f6463a3f5ab [ 130.292303] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055b6786edda8 [ 130.299443] RBP: 000055b6786edd40 R08: 0000000000000000 R09: 0000000000000000 [ 130.306584] R10: 00007f6463b9eac0 R11: 0000000000000206 R12: 000055b6786edda8 [ 130.313731] R13: 0000000000000000 R14: 000055b6786edda8 R15: 00007fff22f995f8 [ 130.320875] [ 130.323081] ---[ end trace eff7156d56b5cf25 ]--- cat /sys/class/dma/dma0chan*/in_use would get the wrong result. 2 2 2 Fixes: d2f4f99db3e9 ("dmaengine: Rework dma_chan_get") Signed-off-by: Koba Ko Reviewed-by: Jie Hai Test-by: Jie Hai Reviewed-by: Jerry Snitselaar Reviewed-by: Dave Jiang Tested-by: Joel Savitz Link: https://lore.kernel.org/r/20221201030050.978595-1-koba.ko@canonical.com Signed-off-by: Vinod Koul

dmaengine: remove DMA_MEMCPY_SG once again

2022-06-27T06:31:40Z

This was removed before due to the complete lack of users, but 3218910fd585 ("dmaengine: Add core function and capability check for DMA_MEMCPY_SG") and 29cf37fa6dd9 ("dmaengine: Add consumer for the new DMA_MEMCPY_SG API function.") added it back despite still not having any users whatsoever. Fixes: 3218910fd585 ("dmaengine: Add core function and capability check for DMA_MEMCPY_SG") Fixes: 29cf37fa6dd9 ("dmaengine: Add consumer for the new DMA_MEMCPY_SG API function.") Signed-off-by: Christoph Hellwig Acked-by: Michal Simek Link: https://lore.kernel.org/r/20220606074733.622616-1-hch@lst.de Signed-off-by: Vinod Koul

dmaengine: Remove a useless mutex

2022-04-11T14:22:40Z

According to lib/idr.c, The IDA handles its own locking. It is safe to call any of the IDA functions without synchronisation in your code. so the 'chan_mutex' mutex can just be removed. It is here only to protect some ida_alloc()/ida_free() calls. Signed-off-by: Christophe JAILLET Link: https://lore.kernel.org/r/7180452c1d77b039e27b6f9418e0e7d9dd33c431.1644140845.git.christophe.jaillet@wanadoo.fr Signed-off-by: Vinod Koul

dmaengine: Add core function and capability check for DMA_MEMCPY_SG

2021-11-22T06:08:05Z

This is the old DMA_SG interface that was removed in commit c678fa66341c ("dmaengine: remove DMA_SG as it is dead code in kernel"). It has been renamed to DMA_MEMCPY_SG to better match the MEMSET and MEMSET_SG naming convention. It should only be used for mem2mem copies, either main system memory or CPU-addressable device memory (like video memory on a PCI graphics card). Bringing back this interface was prompted by the need to use the Xilinx CDMA device for mem2mem SG transfers. Signed-off-by: Adrian Larumbe Link: https://lore.kernel.org/r/20211101180825.241048-3-adrianml@alumnos.upm.es Signed-off-by: Vinod Koul

dmaengine: Remove redundant initialization of variable err

2021-10-18T04:08:05Z

The variable err is being initialized with a value that is never read, it is being updated later on. The assignment is redundant and can be removed and move the declaration into the local scope. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20211015123447.27560-1-colin.king@canonical.com Signed-off-by: Vinod Koul

dmaengine: Fix a double free in dma_async_device_register

2021-04-12T09:35:58Z

In the first list_for_each_entry() macro of dma_async_device_register, it gets the chan from list and calls __dma_async_device_channel_register (..,chan). We can see that chan->local is allocated by alloc_percpu() and it is freed chan->local by free_percpu(chan->local) when __dma_async_device_channel_register() failed. But after __dma_async_device_channel_register() failed, the caller will goto err_out and freed the chan->local in the second time by free_percpu(). The cause of this problem is forget to set chan->local to NULL when chan->local was freed in __dma_async_device_channel_register(). My patch sets chan->local to NULL when the callee failed to avoid double free. Fixes: d2fb0a0438384 ("dmaengine: break out channel registration") Signed-off-by: Lv Yunlong Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/20210331014458.3944-1-lyl2019@mail.ustc.edu.cn Signed-off-by: Vinod Koul

dmaengine: move channel device_node deletion to driver

2021-01-19T16:40:52Z

Channel device_node deletion is managed by the device driver rather than the dmaengine core. The deletion was accidentally introduced when making channel unregister dynamic. It causes xilinx_dma module to crash on unload as reported by Radhey. Remove chan->device_node delete in dmaengine and also fix up idxd driver. [ 42.142705] Internal error: Oops: 96000044 [#1] SMP [ 42.147566] Modules linked in: xilinx_dma(-) clk_xlnx_clock_wizard uio_pdrv_genirq [ 42.155139] CPU: 1 PID: 2075 Comm: rmmod Not tainted 5.10.1-00026-g3a2e6dd7a05-dirty #192 [ 42.163302] Hardware name: Enclustra XU5 SOM (DT) [ 42.167992] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) [ 42.173996] pc : xilinx_dma_chan_remove+0x74/0xa0 [xilinx_dma] [ 42.179815] lr : xilinx_dma_chan_remove+0x70/0xa0 [xilinx_dma] [ 42.185636] sp : ffffffc01112bca0 [ 42.188935] x29: ffffffc01112bca0 x28: ffffff80402ea640 xilinx_dma_chan_remove+0x74/0xa0: __list_del at ./include/linux/list.h:112 (inlined by) __list_del_entry at./include/linux/list.h:135 (inlined by) list_del at ./include/linux/list.h:146 (inlined by) xilinx_dma_chan_remove at drivers/dma/xilinx/xilinx_dma.c:2546 Fixes: e81274cd6b52 ("dmaengine: add support to dynamic register/unregister of channels") Reported-by: Radhey Shyam Pandey Signed-off-by: Dave Jiang Tested-by: Radhey Shyam Pandey Link: https://lore.kernel.org/r/161099092469.2495902.5064826526660062342.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Vinod Koul Cc: stable@vger.kernel.org # 5.9+

dmaengine: fix error codes in channel_register()

2020-11-18T12:21:51Z

The error codes were not set on some of these error paths. Also the error handling was more confusing than it needed to be so I cleaned it up and shuffled it around a bit. Fixes: d2fb0a043838 ("dmaengine: break out channel registration") Signed-off-by: Dan Carpenter Reviewed-by: Peter Ujfalusi Link: https://lore.kernel.org/r/20201113101631.GE168908@mwanda Signed-off-by: Vinod Koul

dmaengine: Save few bytes and increase readability of dma_request_chan()

2020-09-03T06:52:35Z

Split IS_ERR_OR_NULL() check followed by additional conditional to two simple conditionals. This increases readability and saves memory: Function old new delta dma_request_chan 700 697 -3 Total: Before=10224, After=10221, chg -0.03% Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200828144519.14483-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul

dmaengine: Mark dma_request_slave_channel() deprecated

2020-09-03T06:51:03Z

New drivers should use dma_request_chan() instead dma_request_slave_channel() dma_request_slave_channel() is a simple wrapper for dma_request_chan() eating up the error code for channel request failure and makes deferred probing impossible. Move the dma_request_slave_channel() into the header as inline function, mark it as deprecated. Signed-off-by: Peter Ujfalusi Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200828110507.22407-1-peter.ujfalusi@ti.com Signed-off-by: Vinod Koul