Revision d3e33ff59facec005e48ba3360502b73a04e4b4e authored by Bartlomiej Zolnierkiewicz on 05 August 2008, 16:16:59 UTC, committed by Bartlomiej Zolnierkiewicz on 05 August 2008, 16:16:59 UTC
On Monday 28 July 2008, Benjamin Herrenschmidt wrote: [...] > Vector: 300 (Data Access) at [c58b7b80] > pc: c014f264: elv_may_queue+0x10/0x44 > lr: c0152750: get_request+0x2c/0x2c0 > sp: c58b7c30 > msr: 1032 > dar: c > dsisr: 40000000 > current = 0xc58aaae0 > pid = 854, comm = media-bay > enter ? for help > mon> t > [c58b7c40] c0152750 get_request+0x2c/0x2c0 > [c58b7c70] c0152a08 get_request_wait+0x24/0xec > [c58b7cc0] c0225674 ide_cd_queue_pc+0x58/0x1a0 > [c58b7d40] c022672c ide_cdrom_packet+0x9c/0xdc > [c58b7d70] c0261810 cdrom_get_disc_info+0x60/0xd0 > [c58b7dc0] c026208c cdrom_mrw_exit+0x1c/0x11c > [c58b7e30] c0260f7c unregister_cdrom+0x84/0xe8 > [c58b7e50] c022395c ide_cd_release+0x80/0x84 > [c58b7e70] c0163650 kref_put+0x54/0x6c > [c58b7e80] c0223884 ide_cd_put+0x40/0x5c > [c58b7ea0] c0211100 generic_ide_remove+0x28/0x3c > [c58b7eb0] c01e9d34 __device_release_driver+0x78/0xb4 > [c58b7ec0] c01e9e44 device_release_driver+0x28/0x44 > [c58b7ee0] c01e8f7c bus_remove_device+0xac/0xd8 > [c58b7f00] c01e7424 device_del+0x104/0x198 > [c58b7f20] c01e74d0 device_unregister+0x18/0x30 > [c58b7f40] c02121c4 __ide_port_unregister_devices+0x6c/0x88 > [c58b7f60] c0212398 ide_port_unregister_devices+0x38/0x80 > [c58b7f80] c0208ca4 media_bay_step+0x1cc/0x5c0 > [c58b7fb0] c0209124 media_bay_task+0x8c/0xcc > [c58b7fd0] c00485c0 kthread+0x48/0x84 > [c58b7ff0] c0011b20 kernel_thread+0x44/0x60 The guilty commit turned out to be 08da591e14cf87247ec09b17c350235157a92fc3 ("ide: add ide_device_{get,put}() helpers"). ide_device_put() is called before kref_put() in ide_cd_put() so IDE device is already gone by the time ide_cd_release() is reached. Fix it by calling ide_device_get() before kref_get() and ide_device_put() after kref_put() in all affected device drivers. v2: Brown paper bag time. In v1 cd->drive was referenced after dropping last reference on cd object (which could result in OOPS in ide_device_put() as reported/debugged by Mariusz Kozlowski). Fix it by caching cd->drive in the local variable (fix other device drivers too). Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Borislav Petkov <petkovbb@gmail.com> Tested-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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Kbuild
#
# Kbuild for top-level directory of the kernel
# This file takes care of the following:
# 1) Generate bounds.h
# 2) Generate asm-offsets.h (may need bounds.h)
# 3) Check for missing system calls
#####
# 1) Generate bounds.h
bounds-file := include/linux/bounds.h
always := $(bounds-file)
targets := $(bounds-file) kernel/bounds.s
quiet_cmd_bounds = GEN $@
define cmd_bounds
(set -e; \
echo "#ifndef __LINUX_BOUNDS_H__"; \
echo "#define __LINUX_BOUNDS_H__"; \
echo "/*"; \
echo " * DO NOT MODIFY."; \
echo " *"; \
echo " * This file was generated by Kbuild"; \
echo " *"; \
echo " */"; \
echo ""; \
sed -ne $(sed-y) $<; \
echo ""; \
echo "#endif" ) > $@
endef
# We use internal kbuild rules to avoid the "is up to date" message from make
kernel/bounds.s: kernel/bounds.c FORCE
$(Q)mkdir -p $(dir $@)
$(call if_changed_dep,cc_s_c)
$(obj)/$(bounds-file): kernel/bounds.s Kbuild
$(Q)mkdir -p $(dir $@)
$(call cmd,bounds)
#####
# 2) Generate asm-offsets.h
#
offsets-file := include/asm/asm-offsets.h
always += $(offsets-file)
targets += $(offsets-file)
targets += arch/$(SRCARCH)/kernel/asm-offsets.s
# Default sed regexp - multiline due to syntax constraints
define sed-y
"/^->/{s:->#\(.*\):/* \1 */:; \
s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
s:->::; p;}"
endef
quiet_cmd_offsets = GEN $@
define cmd_offsets
(set -e; \
echo "#ifndef __ASM_OFFSETS_H__"; \
echo "#define __ASM_OFFSETS_H__"; \
echo "/*"; \
echo " * DO NOT MODIFY."; \
echo " *"; \
echo " * This file was generated by Kbuild"; \
echo " *"; \
echo " */"; \
echo ""; \
sed -ne $(sed-y) $<; \
echo ""; \
echo "#endif" ) > $@
endef
# We use internal kbuild rules to avoid the "is up to date" message from make
arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
$(obj)/$(bounds-file) FORCE
$(Q)mkdir -p $(dir $@)
$(call if_changed_dep,cc_s_c)
$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s Kbuild
$(call cmd,offsets)
#####
# 3) Check for missing system calls
#
quiet_cmd_syscalls = CALL $<
cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags)
PHONY += missing-syscalls
missing-syscalls: scripts/checksyscalls.sh FORCE
$(call cmd,syscalls)
# Delete all targets during make clean
clean-files := $(addprefix $(objtree)/,$(filter-out $(bounds-file) $(offsets-file),$(targets)))
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